HomeMy WebLinkAboutOWTS Design Packet 07.03.2019July 3, 2019
Mr. Andy Schwaller, Building Official
Garfield County Building Department
108 8th Street
Glenwood Springs, CO 81601
RE: Daniels OWTS
Lots 6 and 7, Quicksilver Court Subdivision
Section 22, TS, R93W
Rifle, CO 81650
Dear Andy,
SSGM
www.sgm-inc.com
The purpose of this letter is to provide you soils and design information relative to a tactile soils analysis
that SGM has performed on behalf of Jody Daniels in support of the installation of an OWTS on each of
lots 6 & 7 of Quicksilver Court Subdivision located on Grass Mesa in Rifle, Colorado. The subdivision site
sits on Grass Mesa south of the City of Rifle with each lot in the 10 acre +/- size. The lots are within
Section 22 of Township 6 South, Range 93 West. The lot 6 parcel number is 217722301006 and the lot 7
parcel number is 217722301007.
This report and design provides Mr. Daniels the direction for which he can construct an OWTS for both
lots considering the future determination of whether he chooses to construct a 3 or 4 bedroom home
on each lot coupled with a 3 bedroom ADU for each lot. On the drawings attached at the end of this
report, you will see the necessary OWTS components for the situation if each lot receives a 4 bedroom
home and a 3 bedroom ADU. If it is determined that each lot is to receive a 3 bedroom home for both
the home and ADU, then the septic tank and soil treatment area for the 4 bedroom design can be
reduced to be identical to the 3 bedroom design provided. Likewise, the design has been prepared in
such a fashion as to allow Mr. Daniels the opportunity to build the OWTS as shown now or as individual
systems later.
To better acquaint you to the site, we have provided Figure 1 on the following page that is an image
from the Garfield County GIS website. Much of the information discussed above is shown on Figure 1.
The specific highlighted lot is that of Lot 7. Lot 6 sits immediately north of Lot 7. The wells that serve
each lot are along the west side of each of the lots, well in excess of 100 feet away from the proposed
soil treatment areas.
GLENWOOD SPRINGS 118 West Sixth St, Suite 200 I Glenwood Springs, CO 81601 1970.945.1004
SSGM
www.sgm-inc.com
21H2f 41M7
217727201903
21 TI2flO1002
27
217722 400261
Account R082628
Owner D N ELS, GEORGE H II
Physical Address QUICKSILVER CT
RIFLE 81650
Mailing Address 176 GH DANIELS BLVD GYPSUM,
CO81637
Acres 10.021
2018 Miit Levy 64.7510
1 n271003 E1
2-177Z OOO54
Figure 1- Site Location
From the NRCS Websoil Survey, the on -site soils (for the STA) are identified as a Vale Silt Loam. The on -
site observations of the Vale Silt loam were characteristic of the silty clay loam identified in the WebSoil
Survey. We have attached a soil report from the NRCS Websoil Survey to describe further the expected
characteristics of the soils determined through our pre -site investigation. Our findings of the soil concur
with those characteristics identified by NRCS in their soil investigation for the Websoil information.
Specifically, our findings are as follows:
1. Depth to ground water is greater than 8 feet.
2. Depth to limiting layer (ie., ground water or bedrock) is greater than 8 feet.
3. Other than a limited depth of topsoil, the soil horizon(s) below the topsoil is a consistent silty
clay loam soil meeting the characteristics of the Soil Type 4 in Table 10-1 of Regulation 43 from
CDPHE.
4. The soil structure grade was a moderate structure with approximately 50% peds found.
GLENWOOD SPRINGS 118 West Sixth St, Suite 200 I Glenwood Springs, CO 81601 1970.945.1004
SSGM
www.sgm-inc.com
5. The No. 10 sieve and smaller particles had a blocky/granular soil structure.
6. The sample contained less than 35% rock.
7. The ribbon size from tactile analysis revealed a larger than 2 inch ribbon with a small amount of
grit and a less than smooth texture.
8. Given these results, the classification for these soils is a Silty Clay Loam, or as previously stated,
a Type 4 Soil per Regulation 43 Table 10-1. (GARCO Table 10-1)
9. The depth of this soil layer exceeds 8 feet with no groundwater, bedrock nor other limiting layer
encountered.
The proposed OWTS for each lot will consist of either two (2) 1000 gallon septic tanks (for two 3
bedroom homes) or a 1000 gallon septic tank (for 3 bedroom ADU) in concert with a 1250 gallon septic
tank (for 4 bedroom home) with gravity flow from the second compartment of the tanks to a
distribution box and ultimately the Infiltrator Quick4 trench systems located north and east of the
homes. Each building will have its own dedicated septic tank with distribution box and infiltrator
trenches.
• The soil tactile analysis reveals a Type 4 soil which is reflective of percolation rates of 76-90 mpi.
The loading rate for the Type 4 soil and TL1 is 0.20 gallons/sf/day.
• We are recommending constructing the STA in the Vale silt loam located just north and east of
each of the building sites. This will accommodate a gravity system to infiltrator trenches.
Gravity Trench System
As you will see on the schematic drawings for this alternative and the information attached, the homes
will need to utilize either a 1,000 gallon septic tank (for 3 bedrooms) or a 1,250 gallon septic tank (for 4
bedrooms). The final determination will be identified at building permit submittal. The tanks are
reflected as being a precast concrete tank (Valley Precast manufactured). From the septic tank, the
effluent would then flow by gravity to the distribution box for the Soil Treatment Area (STA) which is
proposed to be Infiltrator Quick4 chambers constructed in a trench format. A variety of bends and clean
outs would need to be installed from the tanks to the distribution box. At the distribution box, we are
recommending that Polylok flow distribution weirs be installed to assure equal effluent distribution to
each of the infiltrator trenches. Each of the chambered trenches can be installed at a constant level (ie.,
24 to 48" below grade) as equal flow distribution is being accomplished through the distribution box and
weirs. There are to be 6 trenches with 22 units for the 3 bedroom design and 7 trenches and 25 units
for the 4 bedroom design.
Standard end caps are proposed on the end of each trench along with inspection ports. The piping from
the tank, distribution box and infiltrator trenches shall be a minimum diameter of 4" diameter ASTM
3034 PVC. The location of the tank, distribution box, gravity pipe route and infiltrator trenches will be
GLENWOOD SPRINGS 118 West Sixth St, Suite 200 I Glenwood Springs, CO 81601 1970.945.1004
SSGM
www.sgm-inc.com
specified in the attached drawing plan of this package. Note that the drawing package is prepared in a
schematic format that relies on the contractor to provide adequate grading to accomplish the intent of
the design. In this manner, it is anticipated that the contractor can provide routing modifications to
make sure that the grading works for the site.
Note that the component construction for the replacement system will need to follow the requirements
of Sections 43.8, 43.9 and 43.10 of regulation 43 (as adopted by Garfield County) for the tank,
distribution box, piping and STA as applicable. We have attached a copy of each of these sections for
reference by the contractor to assure each component construction is adequately addressed.
Upon your receipt and review, if you have any questions, please don't hesitate to call.
Respectfully,
S
Je'f-fie$ S. Simonson, PE, CFM
Principal
GLENWOOD SPRINGS 118 West Sixth St, Suite 200 I Glenwood Springs, CO 81601 1970.945.1004
OWTS Design Report and Calculations
Client: Jody Daniels Project Location: Section 22
176 GH Daniels Blvd. Township 6N
Gypsum, CO 81637 Range 93W
Date:
17-Jun-19 Lots 6 & 7, Quicksilver Ct. Subdivison
Rifle, Garfield County, Colorado
Flow Data for the OWTS Design
1 Home Use (3 Bedroom Home)
450
Total= 450
For Home Use, 2 persons per bedroom and 75 gallons per day per person, BOD5 = 0.06
#/person/day
Home Use
Totals:
Soil Data for the OWTS
450 gpd 0.48 #/day
450 gpd 0.48 #/day
2 Data from on -site soil observations:
On site textural analysis reveals Blocky, Moderate Silty Clay
At a depth of 8', neither bedrock or groundwater have been encountered.
Data from the web soil survey indicates a Vale Silt Loam exists.
Average of 3 percolation holes:
N/A mpi (Soil Tactile Analysis Perfomed)
Given the consideration of all data, the Long Term Acceptance Rate to use is 0.20 gallons/sf/day
Septic Tank Sizing
3 Flow calculated from above: 450 gpd
48 hour detention time for septic tank sizing; Volume= 900 gpd
Install a 1000 gallon tank for three bedrooms
Dosing Tank Sizing
4 Flow calculated from above:
450 gpd
Dose rate is ADF/4: 112.5 gpd
Go with 250 gallon dosing tank (if used)
Sizing of Absorption Field or Soil Treatment Area
5 Going with a soil type4 and Treatment Level 1, LTAR = 0.2 g/sf/d
For a pressure dosed system, size adjustment factor is 1.0 for a bed configuration
For a gravity system, the size adjustment factor shall be 1.2 for a bed configuration
For a gravity trench system, adjustment factor = 1.0
For a pressure dosed trench system, adjustment factor = 0.8
For use of chambers: size adustment factor is 0.7
STA= Flow/LTAR 2250 square feet (unfactored)
For a bed system, gravity flow, adjust size to 1.2*2250=
For a chamber system, gravity flow, adjust size to 0.7*2250=
Incorporating a pressure dosed system, adjust size to 0.8*1575=
For a chamber system in a trench configuration, length=
(this would equate to 6 runs of 88 feet each)
2700 square feet
1575 square feet
1260 square feet
525 feet (Gravity)
With the effective length of a Quick4 chamber at 4', use 21 chambers per trench for five trenches
For a chamber system in a trench configuration, length=
(this would equate to 5 runs of 84 feet each)
420 feet (Pressure
dosed)
With the effective length of a Quick4 chamber at 4', use 22 chambers per trench for six trenches
if building a gravity fed system.
With the effective length of a Quick4 chamber at 4', use 21 chambers per trench for five trenches
if building a pressure dosed system.
OWTS Design Report and Calculations
Client: Jody Daniels Project Location: Section 22
176 GH Daniels Blvd. Township 6N
Gypsum, CO 81637 Range 93W
Date:
17-Jun-19 Lots 6 & 7, Quicksilver Ct. Subdivison
Rifle, Garfield County, Colorado
Flow Data for the OWTS Design
1 Home Use (4 Bedroom Home)
600
Total= 600
For Home Use, 2 persons per bedroom and 75 gallons per day per person, BOD5 = 0.06
#/person/day
Home Use
Totals:
Soil Data for the OWTS
600 gpd 0.48 #/day
600 gpd 0.48 #/day
2 Data from on -site soil observations:
On site textural analysis reveals Blocky, Moderate Silty Clay
At a depth of 8', neither bedrock or groundwater have been encountered.
Data from the web soil survey indicates a Vale Silt Loam exists.
Average of 3 percolation holes:
N/A mpi (Soil Tactile Analysis Perfomed)
Given the consideration of all data, the Long Term Acceptance Rate to use is 0.20 gallons/sf/day
Septic Tank Sizing
3 Flow calculated from above: 600 gpd
48 hour detention time for septic tank sizing; Volume= 1200 gpd
Install a 1250 gallon tank for three bedrooms
Dosing Tank Sizing
4 Flow calculated from above:
600 gpd
Dose rate is ADF/4 plus drainback: 150 gpd
Go with 250 gallon dosing tank (if used)
For pressure distribution, 1.5 gallons per orfice
Sizing of Absorption Field or Soil Treatment Area
5 Going with a soil type4 and Treatment Level 1, LTAR = 0.2 g/sf/d
For a pressure dosed system, size adjustment factor is 1.0 for a bed configuration
For a gravity system, the size adjustment factor shall be 1.2 for a bed configuration
For a gravity trench system, adjustment factor = 1.0
For a pressure dosed trench system, adjustment factor = 0.8
For use of chambers: size adustment factor is 0.7
STA= Flow/LTAR 3000 square feet (unfactored)
For a bed system, gravity flow, adjust size to 1.2*3000=
For a chamber system, gravity flow, adjust size to 0.7*2700=
Incorporating a pressure dosed system, adjust size to 0.8*2100=
For a chamber system in a trench configuration, length=
(this would equate to 7 runs of 100 feet each)
2700 square feet
2100 square feet
1680 square feet
700 feet (Gravity)
With the effective length of a Quick4 chamber at 4', use 21 chambers per trench for five trenches
For a chamber system in a trench configuration, length=
(this would equate to 6 runs of 93 feet each)
560 feet (Pressure
dosed)
With the effective length of a Quick4 chamber at 4', use 25 chambers per trench for seven trenches
if building a gravity fed system.
With the effective length of a Quick4 chamber at 4', use 24 chambers per trench for six trenches
if building a pressure dosed system.
USDA United States
Department of
Agr culture
RCS
Natural
Resources
Conservation
Service
A product of the National
Cooperative Soil Survey,
a joint effort of the United
States Department of
Agriculture and other
Federal agencies, State
agencies including the
Agricultural Experiment
Stations, and local
participants
Custom Soil Resource
Report for
Rifle Area, Colorado,
Parts of Garfield and
Mesa Counties
July 5, 2019
Preface
Soil surveys contain information that affects land use planning in survey areas.
They highlight soil limitations that affect various land uses and provide information
about the properties of the soils in the survey areas. Soil surveys are designed for
many different users, including farmers, ranchers, foresters, agronomists, urban
planners, community officials, engineers, developers, builders, and home buyers.
Also, conservationists, teachers, students, and specialists in recreation, waste
disposal, and pollution control can use the surveys to help them understand,
protect, or enhance the environment.
Various land use regulations of Federal, State, and local governments may impose
special restrictions on land use or land treatment. Soil surveys identify soil
properties that are used in making various land use or land treatment decisions.
The information is intended to help the land users identify and reduce the effects of
soil limitations on various land uses. The landowner or user is responsible for
identifying and complying with existing laws and regulations.
Although soil survey information can be used for general farm, local, and wider area
planning, onsite investigation is needed to supplement this information in some
cases. Examples include soil quality assessments (http://www.nrcs.usda.gov/wps/
portal/nrcs/main/soils/health/) and certain conservation and engineering
applications. For more detailed information, contact your local USDA Service Center
(https://offices.sc.egov.usda.gov/locator/app?agency=nres) or your NRCS State Soil
Scientist (http://www.nres.usda.gov/wps/portal/nres/detail/soils/contactus/?
cid=nrcs142p2_053951).
Great differences in soil properties can occur within short distances. Some soils are
seasonally wet or subject to flooding. Some are too unstable to be used as a
foundation for buildings or roads. Clayey or wet soils are poorly suited to use as
septic tank absorption fields. A high water table makes a soil poorly suited to
basements or underground installations.
The National Cooperative Soil Survey is a joint effort of the United States
Department of Agriculture and other Federal agencies, State agencies including the
Agricultural Experiment Stations, and local agencies. The Natural Resources
Conservation Service (NRCS) has leadership for the Federal part of the National
Cooperative Soil Survey.
Information about soils is updated periodically. Updated information is available
through the NRCS Web Soil Survey, the site for official soil survey information.
The U.S. Department of Agriculture (USDA) prohibits discrimination in all its
programs and activities on the basis of race, color, national origin, age, disability,
and where applicable, sex, marital status, familial status, parental status, religion,
sexual orientation, genetic information, political beliefs, reprisal, or because all or a
part of an individual's income is derived from any public assistance program. (Not
all prohibited bases apply to all programs.) Persons with disabilities who require
2
alternative means for communication of program information (Braille, large print,
audiotape, etc.) should contact USDA's TARGET Center at (202) 720-2600 (voice
and TDD). To file a complaint of discrimination, write to USDA, Director, Office of
Civil Rights, 1400 Independence Avenue, S.W., Washington, D.C. 20250-9410 or
call (800) 795-3272 (voice) or (202) 720-6382 (TDD). USDA is an equal opportunity
provider and employer.
3
Contents
Preface 2
How Soil Surveys Are Made 5
Soil Map 8
Soil Map (Daniels OWTS) 9
Legend 10
Map Unit Legend (Daniels OWTS) 12
Map Unit Descriptions (Daniels OWTS) 12
Rifle Area, Colorado, Parts of Garfield and Mesa Counties 14
45—Morval-Tridell complex, 6 to 25 percent slopes 14
67—Torriorthents-Rock outcrop complex, steep 15
68—Vale silt loam, 3 to 6 percent slopes 17
Soil Information for All Uses 19
Soil Reports 19
Soil Physical Properties 19
Engineering Properties (Daniels OWTS) 19
4
How Soil Surveys Are Made
Soil surveys are made to provide information about the soils and miscellaneous
areas in a specific area. They include a description of the soils and miscellaneous
areas and their location on the landscape and tables that show soil properties and
limitations affecting various uses. Soil scientists observed the steepness, length,
and shape of the slopes; the general pattern of drainage; the kinds of crops and
native plants; and the kinds of bedrock. They observed and described many soil
profiles. A soil profile is the sequence of natural layers, or horizons, in a soil. The
profile extends from the surface down into the unconsolidated material in which the
soil formed or from the surface down to bedrock. The unconsolidated material is
devoid of roots and other living organisms and has not been changed by other
biological activity.
Currently, soils are mapped according to the boundaries of major land resource
areas (MLRAs). MLRAs are geographically associated land resource units that
share common characteristics related to physiography, geology, climate, water
resources, soils, biological resources, and land uses (USDA, 2006). Soil survey
areas typically consist of parts of one or more MLRA.
The soils and miscellaneous areas in a survey area occur in an orderly pattern that
is related to the geology, landforms, relief, climate, and natural vegetation of the
area. Each kind of soil and miscellaneous area is associated with a particular kind
of landform or with a segment of the landform. By observing the soils and
miscellaneous areas in the survey area and relating their position to specific
segments of the landform, a soil scientist develops a concept, or model, of how they
were formed. Thus, during mapping, this model enables the soil scientist to predict
with a considerable degree of accuracy the kind of soil or miscellaneous area at a
specific location on the landscape.
Commonly, individual soils on the landscape merge into one another as their
characteristics gradually change. To construct an accurate soil map, however, soil
scientists must determine the boundaries between the soils. They can observe only
a limited number of soil profiles. Nevertheless, these observations, supplemented
by an understanding of the soil -vegetation -landscape relationship, are sufficient to
verify predictions of the kinds of soil in an area and to determine the boundaries.
Soil scientists recorded the characteristics of the soil profiles that they studied. They
noted soil color, texture, size and shape of soil aggregates, kind and amount of rock
fragments, distribution of plant roots, reaction, and other features that enable them
to identify soils. After describing the soils in the survey area and determining their
properties, the soil scientists assigned the soils to taxonomic classes (units).
Taxonomic classes are concepts. Each taxonomic class has a set of soil
characteristics with precisely defined limits. The classes are used as a basis for
comparison to classify soils systematically. Soil taxonomy, the system of taxonomic
classification used in the United States, is based mainly on the kind and character
of soil properties and the arrangement of horizons within the profile. After the soil
5
Custom Soil Resource Report
scientists classified and named the soils in the survey area, they compared the
individual soils with similar soils in the same taxonomic class in other areas so that
they could confirm data and assemble additional data based on experience and
research.
The objective of soil mapping is not to delineate pure map unit components; the
objective is to separate the landscape into landforms or landform segments that
have similar use and management requirements. Each map unit is defined by a
unique combination of soil components and/or miscellaneous areas in predictable
proportions. Some components may be highly contrasting to the other components
of the map unit. The presence of minor components in a map unit in no way
diminishes the usefulness or accuracy of the data. The delineation of such
landforms and landform segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, onsite
investigation is needed to define and locate the soils and miscellaneous areas.
Soil scientists make many field observations in the process of producing a soil map.
The frequency of observation is dependent upon several factors, including scale of
mapping, intensity of mapping, design of map units, complexity of the landscape,
and experience of the soil scientist. Observations are made to test and refine the
soil -landscape model and predictions and to verify the classification of the soils at
specific locations. Once the soil -landscape model is refined, a significantly smaller
number of measurements of individual soil properties are made and recorded.
These measurements may include field measurements, such as those for color,
depth to bedrock, and texture, and laboratory measurements, such as those for
content of sand, silt, clay, salt, and other components. Properties of each soil
typically vary from one point to another across the landscape.
Observations for map unit components are aggregated to develop ranges of
characteristics for the components. The aggregated values are presented. Direct
measurements do not exist for every property presented for every map unit
component. Values for some properties are estimated from combinations of other
properties.
While a soil survey is in progress, samples of some of the soils in the area generally
are collected for laboratory analyses and for engineering tests. Soil scientists
interpret the data from these analyses and tests as well as the field -observed
characteristics and the soil properties to determine the expected behavior of the
soils under different uses. Interpretations for all of the soils are field tested through
observation of the soils in different uses and under different levels of management.
Some interpretations are modified to fit local conditions, and some new
interpretations are developed to meet local needs. Data are assembled from other
sources, such as research information, production records, and field experience of
specialists. For example, data on crop yields under defined levels of management
are assembled from farm records and from field or plot experiments on the same
kinds of soil.
Predictions about soil behavior are based not only on soil properties but also on
such variables as climate and biological activity. Soil conditions are predictable over
long periods of time, but they are not predictable from year to year. For example,
soil scientists can predict with a fairly high degree of accuracy that a given soil will
have a high water table within certain depths in most years, but they cannot predict
that a high water table will always be at a specific level in the soil on a specific date.
After soil scientists located and identified the significant natural bodies of soil in the
survey area, they drew the boundaries of these bodies on aerial photographs and
6
Custom Soil Resource Report
identified each as a specific map unit. Aerial photographs show trees, buildings,
fields, roads, and rivers, all of which help in locating boundaries accurately.
7
Soil Map
The soil map section includes the soil map for the defined area of interest, a list of
soil map units on the map and extent of each map unit, and cartographic symbols
displayed on the map. Also presented are various metadata about data used to
produce the map, and a description of each soil map unit.
8
39° 30' 30" N
39° 30' 15" N
3
282260
262320
Custom Soil Resource Report
Soil Map (Daniels OWTS)
262380
262440
262500
262560
3
a
3
v
262260 262320 262380 262440 262500 262560
Map Scale: 1:2,340 if printed on A portrait (8.5" x 11") sheet
0 30 60
120
0 100 200
Meters
180
Feet
400 600
or 45 39" W
39° 30' 30" N
39° 30' 15" N
Map projection: Web Mercator Comer coordinates: WG584 Edge tics: UTM Zone 13N WGS84
9
Custom Soil Resource Report
MAP LEGEND
Area of Interest (AOI)
Area of Interest (AOI)
Soils
0
0 Soil Map Unit Lines
Soil Map Unit Polygons
Soil Map Unit Points
Special Point Features
Blowout
la Borrow Pit
Clay Spot
• Closed Depression
• Gravel Pit
Gravelly Spot
• Landfill
Lava Flow
Marsh or swamp
an4 Mine or Quarry
• Miscellaneous Water
• Perennial Water
• Rock Outcrop
▪ Saline Spot
Sandy Spot
Severely Eroded Spot
Sinkhole
Slide or Slip
oa Sodic Spot
A
Spoil Area
Stony Spot
Very Stony Spot
Wet Spot
Other
Special Line Features
Water Features
Streams and Canals
Transportation
H-F Rails
0.10 Interstate Highways
wrapUS Routes
Major Roads
Local Roads
Background
1. Aerial Photography
MAP INFORMATION
The soil surveys that comprise your AOI were mapped at
1:24,000.
Warning: Soil Map may not be valid at this scale.
Enlargement of maps beyond the scale of mapping can cause
misunderstanding of the detail of mapping and accuracy of soil
line placement. The maps do not show the small areas of
contrasting soils that could have been shown at a more detailed
scale.
Please rely on the bar scale on each map sheet for map
measurements.
Source of Map: Natural Resources Conservation Service
Web Soil Survey URL:
Coordinate System: Web Mercator (EPSG:3857)
Maps from the Web Soil Survey are based on the Web Mercator
projection, which preserves direction and shape but distorts
distance and area. A projection that preserves area, such as the
Albers equal-area conic projection, should be used if more
accurate calculations of distance or area are required.
This product is generated from the USDA-NRCS certified data as
of the version date(s) listed below.
Soil Survey Area: Rifle Area, Colorado, Parts of Garfield and
Mesa Counties
Survey Area Data: Version 11, Sep 10, 2018
Soil map units are labeled (as space allows) for map scales
1:50,000 or larger.
Date(s) aerial images were photographed: Dec 31, 2009—Oct
12, 2017
The orthophoto or other base map on which the soil lines were
compiled and digitized probably differs from the background
10
Custom Soil Resource Report
MAP LEGEND MAP INFORMATION
imagery displayed on these maps. As a result, some minor
shifting of map unit boundaries may be evident.
Custom Soil Resource Report
Map Unit Legend (Daniels OWTS)
Map Unit Symbol
Map Unit Name
Acres in AOI
Percent of AOI
45
Morval-Tridell complex, 6 to 25
percent slopes
6.4
0.8
28.4%
67
Torriorthents-Rock outcrop
complex, steep
3.6%
68
Vale silt loam, 3 to 6 percent
slopes
15.3
68.0%
Totals for Area of Interest
22.5
100.0%
Map Unit Descriptions (Daniels OWTS)
The map units delineated on the detailed soil maps in a soil survey represent the
soils or miscellaneous areas in the survey area. The map unit descriptions, along
with the maps, can be used to determine the composition and properties of a unit.
A map unit delineation on a soil map represents an area dominated by one or more
major kinds of soil or miscellaneous areas. A map unit is identified and named
according to the taxonomic classification of the dominant soils. Within a taxonomic
class there are precisely defined limits for the properties of the soils. On the
landscape, however, the soils are natural phenomena, and they have the
characteristic variability of all natural phenomena. Thus, the range of some
observed properties may extend beyond the limits defined for a taxonomic class.
Areas of soils of a single taxonomic class rarely, if ever, can be mapped without
including areas of other taxonomic classes. Consequently, every map unit is made
up of the soils or miscellaneous areas for which it is named and some minor
components that belong to taxonomic classes other than those of the major soils.
Most minor soils have properties similar to those of the dominant soil or soils in the
map unit, and thus they do not affect use and management. These are called
noncontrasting, or similar, components. They may or may not be mentioned in a
particular map unit description. Other minor components, however, have properties
and behavioral characteristics divergent enough to affect use or to require different
management. These are called contrasting, or dissimilar, components. They
generally are in small areas and could not be mapped separately because of the
scale used. Some small areas of strongly contrasting soils or miscellaneous areas
are identified by a special symbol on the maps. If included in the database for a
given area, the contrasting minor components are identified in the map unit
descriptions along with some characteristics of each. A few areas of minor
components may not have been observed, and consequently they are not
mentioned in the descriptions, especially where the pattern was so complex that it
was impractical to make enough observations to identify all the soils and
miscellaneous areas on the landscape.
The presence of minor components in a map unit in no way diminishes the
usefulness or accuracy of the data. The objective of mapping is not to delineate
pure taxonomic classes but rather to separate the landscape into landforms or
12
Custom Soil Resource Report
landform segments that have similar use and management requirements. The
delineation of such segments on the map provides sufficient information for the
development of resource plans. If intensive use of small areas is planned, however,
onsite investigation is needed to define and locate the soils and miscellaneous
areas.
An identifying symbol precedes the map unit name in the map unit descriptions.
Each description includes general facts about the unit and gives important soil
properties and qualities.
Soils that have profiles that are almost alike make up a soil series. Except for
differences in texture of the surface layer, all the soils of a series have major
horizons that are similar in composition, thickness, and arrangement.
Soils of one series can differ in texture of the surface layer, slope, stoniness,
salinity, degree of erosion, and other characteristics that affect their use. On the
basis of such differences, a soil series is divided into soil phases. Most of the areas
shown on the detailed soil maps are phases of soil series. The name of a soil phase
commonly indicates a feature that affects use or management. For example, Alpha
silt loam, 0 to 2 percent slopes, is a phase of the Alpha series.
Some map units are made up of two or more major soils or miscellaneous areas.
These map units are complexes, associations, or undifferentiated groups.
A complex consists of two or more soils or miscellaneous areas in such an intricate
pattern or in such small areas that they cannot be shown separately on the maps.
The pattern and proportion of the soils or miscellaneous areas are somewhat similar
in all areas. Alpha -Beta complex, 0 to 6 percent slopes, is an example.
An association is made up of two or more geographically associated soils or
miscellaneous areas that are shown as one unit on the maps. Because of present
or anticipated uses of the map units in the survey area, it was not considered
practical or necessary to map the soils or miscellaneous areas separately. The
pattern and relative proportion of the soils or miscellaneous areas are somewhat
similar. Alpha -Beta association, 0 to 2 percent slopes, is an example.
An undifferentiated group is made up of two or more soils or miscellaneous areas
that could be mapped individually but are mapped as one unit because similar
interpretations can be made for use and management. The pattern and proportion
of the soils or miscellaneous areas in a mapped area are not uniform. An area can
be made up of only one of the major soils or miscellaneous areas, or it can be made
up of all of them. Alpha and Beta soils, 0 to 2 percent slopes, is an example.
Some surveys include miscellaneous areas. Such areas have little or no soil
material and support little or no vegetation. Rock outcrop is an example.
13
Custom Soil Resource Report
Rifle Area, Colorado, Parts of Garfield and Mesa Counties
45—Morval-Tridell complex, 6 to 25 percent slopes
Map Unit Setting
National map unit symbol: jnyd
Elevation: 6,500 to 8,000 feet
Farmland classification: Not prime farmland
Map Unit Composition
Morval and similar soils: 55 percent
Tridell and similar soils: 30 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Morval
Setting
Landform: Mesas, alluvial fans
Down -slope shape: Convex, linear
Across -slope shape: Convex, linear
Parent material: Reworked alluvium derived from sandstone and/or reworked
alluvium derived from basalt
Typical profile
H1 - 0 to 5 inches: loam
H2 - 5 to 17 inches: clay loam
H3 - 17 to 27 inches: stony clay loam
H4 - 27 to 60 inches: stony loam
Properties and qualities
Slope: 6 to 12 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat): Moderately high (0.20
to 0.60 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 25 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
Available water storage in profile: Moderate (about 8.4 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 4e
Hydrologic Soil Group: C
Ecological site: Deep Loam (R048AY292C0)
Hydric soil rating: No
Description of Tridell
Setting
Landform: Alluvial fans, mesas
Down -slope shape: Convex
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Custom Soil Resource Report
Across -slope shape: Convex
Parent material: Reworked alluvium derived from sandstone and/or reworked
alluvium derived from basalt
Typical profile
H1 - 0 to 10 inches: stony loam
H2 - 10 to 60 inches: very stony loam
Properties and qualities
Slope: 6 to 25 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: Low
Capacity of the most limiting layer to transmit water (Ksat): Moderately high to
high (0.60 to 6.00 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 30 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
Available water storage in profile: Low (about 5.2 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 6e
Hydrologic Soil Group: A
Hydric soil rating: No
67—Torriorthents-Rock outcrop complex, steep
Map Unit Setting
National map unit symbol: jnz5
Elevation: 5,800 to 8,500 feet
Mean annual precipitation: 10 to 15 inches
Mean annual air temperature: 39 to 46 degrees F
Frost -free period: 80 to 105 days
Farmland classification: Not prime farmland
Map Unit Composition
Torriorthents, steep, and similar soils: 60 percent
Rock outcrop, steep: 25 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Torriorthents, Steep
Setting
Landform: Mountainsides
Landform position (two-dimensional): Footslope
Landform position (three-dimensional): Mountainflank, base slope
Down -slope shape: Concave, convex
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Custom Soil Resource Report
Across -slope shape: Concave, convex
Parent material: Stony, basaltic alluvium derived from sandstone and shale
Typical profile
H1 - 0 to 4 inches: variable
H2 - 4 to 30 inches: fine sandy loam
H3 - 30 to 34 inches: unweathered bedrock
Properties and qualities
Slope: 15 to 70 percent
Depth to restrictive feature: 4 to 30 inches to lithic bedrock
Natural drainage class: Well drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat): Moderately low to
moderately high (0.06 to 0.20 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 5 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
Available water storage in profile: Very low (about 2.4 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 7e
Hydrologic Soil Group: D
Hydric soil rating: No
Description of Rock Outcrop, Steep
Setting
Landform: Mountainsides
Landform position (three-dimensional): Free face
Down -slope shape: Convex
Across -slope shape: Convex
Typical profile
H1 - 0 to 60 inches: unweathered bedrock
Properties and qualities
Slope: 15 to 70 percent
Depth to restrictive feature: 0 inches to paralithic bedrock
Runoff class: Very high
Capacity of the most limiting layer to transmit water (Ksat): Very low to moderately
high (0.00 to 0.20 in/hr)
Available water storage in profile: Very low (about 0.0 inches)
Interpretive groups
Land capability classification (irrigated): None specified
Land capability classification (nonirrigated): 8s
Hydric soil rating: No
Custom Soil Resource Report
68—Vale silt loam, 3 to 6 percent slopes
Map Unit Setting
National map unit symbol: jnz6
Elevation: 5,000 to 7,200 feet
Farmland classification: Prime farmland if irrigated
Map Unit Composition
Vale and similar soils: 90 percent
Minor components: 10 percent
Estimates are based on observations, descriptions, and transects of the mapunit.
Description of Vale
Setting
Landform: Mesas, alluvial fans, terraces
Landform position (three-dimensional): Tread
Down -slope shape: Convex, linear
Across -slope shape: Convex, linear
Parent material: Calcareous eolian deposits
Typical profile
H1 - 0 to 7 inches: silt loam
H2 - 7 to 11 inches: silt loam
H3 - 11 to 26 inches: silty clay loam
H4 - 26 to 60 inches: silt loam
Properties and qualities
Slope: 3 to 6 percent
Depth to restrictive feature: More than 80 inches
Natural drainage class: Well drained
Runoff class: High
Capacity of the most limiting layer to transmit water (Ksat): Moderately high (0.20
to 0.60 in/hr)
Depth to water table: More than 80 inches
Frequency of flooding: None
Frequency of ponding: None
Calcium carbonate, maximum in profile: 15 percent
Salinity, maximum in profile: Nonsaline to very slightly saline (0.0 to 2.0
mmhos/cm)
Available water storage in profile: High (about 10.5 inches)
Interpretive groups
Land capability classification (irrigated): 3e
Land capability classification (nonirrigated): 3e
Hydrologic Soil Group: C
Ecological site: Deep Loam (R048AY292C0)
Hydric soil rating: No
Custom Soil Resource Report
Minor Components
Morval
Percent of map unit: 10 percent
Hydric soil rating: No
Soil Information for All Uses
Soil Reports
The Soil Reports section includes various formatted tabular and narrative reports
(tables) containing data for each selected soil map unit and each component of
each unit. No aggregation of data has occurred as is done in reports in the Soil
Properties and Qualities and Suitabilities and Limitations sections.
The reports contain soil interpretive information as well as basic soil properties and
qualities. A description of each report (table) is included.
Soil Physical Properties
This folder contains a collection of tabular reports that present soil physical
properties. The reports (tables) include all selected map units and components for
each map unit. Soil physical properties are measured or inferred from direct
observations in the field or laboratory. Examples of soil physical properties include
percent clay, organic matter, saturated hydraulic conductivity, available water
capacity, and bulk density.
Engineering Properties (Daniels OWTS)
This table gives the engineering classifications and the range of engineering
properties for the layers of each soil in the survey area.
Hydrologic soil group is a group of soils having similar runoff potential under similar
storm and cover conditions. The criteria for determining Hydrologic soil group is
found in the National Engineering Handbook, Chapter 7 issued May 2007(http://
directives.sc.egov.usda.gov/OpenNonWebContent.aspx?content=17757.wba).
Listing HSGs by soil map unit component and not by soil series is a new concept for
the engineers. Past engineering references contained lists of HSGs by soil series.
Soil series are continually being defined and redefined, and the list of soil series
names changes so frequently as to make the task of maintaining a single national
list virtually impossible. Therefore, the criteria is now used to calculate the HSG
using the component soil properties and no such national series lists will be
maintained. All such references are obsolete and their use should be discontinued.
Soil properties that influence runoff potential are those that influence the minimum
rate of infiltration for a bare soil after prolonged wetting and when not frozen. These
properties are depth to a seasonal high water table, saturated hydraulic conductivity
after prolonged wetting, and depth to a layer with a very slow water transmission
19
Custom Soil Resource Report
rate. Changes in soil properties caused by land management or climate changes
also cause the hydrologic soil group to change. The influence of ground cover is
treated independently. There are four hydrologic soil groups, A, B, C, and D, and
three dual groups, A/D, B/D, and C/D. In the dual groups, the first letter is for
drained areas and the second letter is for undrained areas.
The four hydrologic soil groups are described in the following paragraphs:
Group A. Soils having a high infiltration rate (low runoff potential) when thoroughly
wet. These consist mainly of deep, well drained to excessively drained sands or
gravelly sands. These soils have a high rate of water transmission.
Group B. Soils having a moderate infiltration rate when thoroughly wet. These
consist chiefly of moderately deep or deep, moderately well drained or well drained
soils that have moderately fine texture to moderately coarse texture. These soils
have a moderate rate of water transmission.
Group C. Soils having a slow infiltration rate when thoroughly wet. These consist
chiefly of soils having a layer that impedes the downward movement of water or
soils of moderately fine texture or fine texture. These soils have a slow rate of water
transmission.
Group D. Soils having a very slow infiltration rate (high runoff potential) when
thoroughly wet. These consist chiefly of clays that have a high shrink -swell
potential, soils that have a high water table, soils that have a claypan or clay layer at
or near the surface, and soils that are shallow over nearly impervious material.
These soils have a very slow rate of water transmission.
Depth to the upper and lower boundaries of each layer is indicated.
Texture is given in the standard terms used by the U.S. Department of Agriculture.
These terms are defined according to percentages of sand, silt, and clay in the
fraction of the soil that is less than 2 millimeters in diameter. "Loam," for example, is
soil that is 7 to 27 percent clay, 28 to 50 percent silt, and less than 52 percent sand.
If the content of particles coarser than sand is 15 percent or more, an appropriate
modifier is added, for example, "gravelly."
Classification of the soils is determined according to the Unified soil classification
system (ASTM, 2005) and the system adopted by the American Association of
State Highway and Transportation Officials (AASHTO, 2004).
The Unified system classifies soils according to properties that affect their use as
construction material. Soils are classified according to particle -size distribution of
the fraction less than 3 inches in diameter and according to plasticity index, liquid
limit, and organic matter content. Sandy and gravelly soils are identified as GW, GP,
GM, GC, SW, SP, SM, and SC; silty and clayey soils as ML, CL, OL, MH, CH, and
OH; and highly organic soils as PT. Soils exhibiting engineering properties of two
groups can have a dual classification, for example, CL-ML.
The AASHTO system classifies soils according to those properties that affect
roadway construction and maintenance. In this system, the fraction of a mineral soil
that is less than 3 inches in diameter is classified in one of seven groups from A-1
through A-7 on the basis of particle -size distribution, liquid limit, and plasticity index.
Soils in group A-1 are coarse grained and low in content of fines (silt and clay). At
the other extreme, soils in group A-7 are fine grained. Highly organic soils are
classified in group A-8 on the basis of visual inspection.
If laboratory data are available, the A-1, A-2, and A-7 groups are further classified
as A-1-a, A-1-b, A-2-4, A-2-5, A-2-6, A-2-7, A-7-5, or A-7-6. As an additional
refinement, the suitability of a soil as subgrade material can be indicated by a group
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Custom Soil Resource Report
index number. Group index numbers range from 0 for the best subgrade material to
20 or higher for the poorest.
Percentage of rock fragments larger than 10 inches in diameter and 3 to 10 inches
in diameter are indicated as a percentage of the total soil on a dry -weight basis. The
percentages are estimates determined mainly by converting volume percentage in
the field to weight percentage. Three values are provided to identify the expected
Low (L), Representative Value (R), and High (H).
Percentage (of soil particles) passing designated sieves is the percentage of the soil
fraction less than 3 inches in diameter based on an ovendry weight. The sieves,
numbers 4, 10, 40, and 200 (USA Standard Series), have openings of 4.76, 2.00,
0.420, and 0.074 millimeters, respectively. Estimates are based on laboratory tests
of soils sampled in the survey area and in nearby areas and on estimates made in
the field. Three values are provided to identify the expected Low (L), Representative
Value (R), and High (H).
Liquid limit and plasticity index (Atterberg limits) indicate the plasticity
characteristics of a soil. The estimates are based on test data from the survey area
or from nearby areas and on field examination. Three values are provided to identify
the expected Low (L), Representative Value (R), and High (H).
References:
American Association of State Highway and Transportation Officials (AASHTO).
2004. Standard specifications for transportation materials and methods of sampling
and testing. 24th edition.
American Society for Testing and Materials (ASTM). 2005. Standard classification of
soils for engineering purposes. ASTM Standard D2487-00.
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Custom Soil Resource Report
Absence of an entry indicates that the data were not estimated. The asterisk '*' denotes the representative texture; other
possible textures follow the dash. The criteria for determining the hydrologic soil group for individual soil components is
found in the National Engineering Handbook, Chapter 7 issued May 2007(http://directives.sc.egov.usda.gov/
OpenNonWebContent.aspx?content=17757.wba). Three values are provided to identify the expected Low (L),
Representative Value (R), and High (H).
Engineering Properties —Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Map unit symbol and
Pct. of
Hydrolo
Depth
USDA texture
Classification
Pct Fragments
Percentage passing sieve number—
Liquid
Plasticit
soil name
map
gic
limit
y index
unit
group
Unified
AASHTO
>10
3-10
4
10
40
200
inches
inches
In
L-R-H
L-R-H
L-R-H
L-R-H
L-R-H
L-R-H
L-R-H
L-R-H
45—Morval-Tridell
complex, 6 to 25
percent slopes
Morval
55
C
0-5
Loam
CL, CL-
A-4
0- 0- 20
0- 0- 20
85-93-1
80-92-1
70-83-
50-63-
25-28
5-8 -10
ML
00
00
95
75
-30
5-17
Clay loam
CL
A-6
0- 0- 20
0- 0- 20
85-93-1
80-92-1
75-88-1
60-70-
30-35
10-15-2
00
00
00
80
-40
0
17-27
Stony clay loam
CL
A-6
10-28-
0-15- 30
75-83-
70-78-
65-75-
50-60-
30-33
10-13-1
45
90
85
85
70
-35
5
27-60
Stony loam
CL, CL-
A-4
10-28-
0-15- 30
75-83-
70-78-
60-70-
45-55-
25-28
5-8 -10
ML, SC,
SC-SM
45
90
85
80
65
-30
Tridell
30
A
=
Stony loam
CL, CL-
A-4
10-28-
0-15- 30
75-83-
70-78-
60-70-
45-55-
25-28
5-8 -10
ML, SC,
SC-SM
45
90
85
80
65
-30
10-60
Very stony loam
CL-ML,
A-2, A-4
25-48-
0-25- 50
45-68-
40-63-
35-58-
25-45-
25-28
5-8 -10
GC -GM,
SC-SM
70
90
85
80
65
-30
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Custom Soil Resource Report
Engineering Properties —Rifle Area, Colorado, Parts of Garfield and Mesa Counties
Map unit symbol and
soil name
Pct. of
map
unit
Hydrolo
gic
group
Depth
USDA texture
Classification
Pct Fragments
Percentage passing sieve number—
Liquid
limit
Plasticit
y index
Unified
AASHTO
>10
inches
3-10
inches
4
10
40
200
In
L-R-H
L-R-H
L-R-H
L-R-H
L-R-H
L-R-H
L-R-H
L-R-H
67—Torriorthents-Rock
outcrop complex,
steep
Torriorthents, steep
60
D
0-4
Variable
—
—
0- 0- 0
0-10- 20
—
—
—
—
—
—
4-30
Fine sandy loam,
loam, clay loam
CL, CL-
ML, SC-
SM, SM
A-2, A-4,
A-6
0- 0- 0
0- 6- 20
65-95-
95
60-90-
90
50-65-
80
25-48-
70
15-25
-35
NP-10-2
0
30-34
Unweathered
bedrock
—
—
—
—
—
—
—
—
—
—
Rock outcrop, steep
25
0-60
Unweathered
bedrock
—
—
—
—
0-7 -14
—
68—Vale silt loam, 3 to
6 percent slopes
Vale
90
C
0-7
Silt loam
ML
A-4
0- 0- 0
0- 0- 0
100-100
-100
100-100
-100
90-95-1
00
70-80-
90
30-33
-35
5-8 -10
7-11
Silt loam
ML
A-4
0- 0- 0
0- 0- 0
100-100
-100
100-100
-100
90-95-1
00
70-80-
90
30-33
-35
5-8 -10
11-26
Silty clay loam
ML
A-4, A-6,
A-7
0- 0- 0
0- 0- 0
100-100
-100
100-100
-100
95-98-1
00
85-90-
95
30-38
-45
5-10-15
26-60
Silt loam
ML
A-4
0- 0- 0
0- 0- 0
100-100
-100
100-100
-100
90-95-1
00
70-80-
90
30-33
-35
5-8 -10
23
1IIIEiiaNtirA ',tiriI',Fi% Witt), 11III
Reception#: 848421
04/22/2014 09 31.33 AM Jean Rlberico
45 of 80 Rec Fee $0 00 Doc Fee 0 00 GARFIELD COUNTY CO
43.8 Design Criteria — General
Table 7-2 On -site Wastewater Treatment System Design Consideration and Treatment
Requirements — Separation Distances from Soil Treatment Area
PRESSURE DOSING REQUIRED
ITEM
OWTS DESIGN
CONSIDERATION
Treatment
Levels 1 and 2
Treatment
Level 2N
Treatment
Level 3
Treatment
Level 3N
Horizontal Separation
Distances
1
Distance from soil
treatment area to on -site
well
Greater than or
equal to 100
feet
Greater than
or equal to
100 feet
Greater than
or equal to
100 feet
Greater than
or equal to 75
feet'
2
Distance from soil
treatment area to pond,
creek, lake, or other
surface water feature
Greater than or
equal to 50 feet
Greater than
or equal to 25
feet
Greater than
or equal to 25
feet
Greater than
or equal to 25
feet
3
Distance from soil
treatment area to dry
gulch or cut bank
Greater than or
equal to 25 feet
Greater than
or equal to 10
feet
Greater than
or equal to 10
feet
Greater than
or equal to 10
feet
Vertical Separation
Distances
4
Depth in feet from soil
treatment area infiltrative
surface to restrictive
layer or ground water
4 feet (3 feet
with pressure
dosing)
Greater than
or equal to 2
feet
Greater than
or equal to 2
feet
Greater than
or equal to 2
feet
NOTE: Treatment levels are defined in Table 6-3.
Reductions in separation distances with higher level treatment may be granted only if the local public health agency regulations
have included provisions for operation and maintenance.
1 Prior to approval, all setback distance reductions to the 100 foot requirement for wells and soil treatment areas must be in
full compliance with the minimum standards and variance requirements of the State of Colorado Division of Water Resources:
Rules and Regulations for Water Well Construction, Pump Installation, Cistern Installation, and Monitoring and Observation
Hole/Well Construction.
43.8 Design Criteria — General
A. Performance: OWTS shall be designed and constructed to achieve the treatment level specified
by the design.
B. Reliability: OWTS shall be designed and constructed such that each component shall function,
when installed and operated, in a manner not adversely affected by normal operating conditions
including erosion, corrosion, vibration, shock, climatic conditions, and usual household chemicals.
Each component shall be free of non-functional protrusions or sharp edges, or other hazards,
which could cause injury to persons, animals, or properties. Design shall be such as to exclude
flies and rodents and other vectors and to prevent the creation of nuisances and public health
hazards and shall provide for efficient operation and maintenance.
41
1111 MidCiiEMIN'1n41 K': rleliAtl'11110 l j' I'i, 1111
Reception#: 848421
04I22i2014 09 31:33 AM Jean Rlberico
48 of 90 Rec Fee•$0 00 Doc Fee:0 0C GRRFIEL_D COUNTY CO
43.8 Design Criteria — General
C. Accessibility for Inspection, Maintenance, and Servicing
1. Septic tanks shall have risers over each access manhole and all risers shall extend to or
above final grade.
2. Each treatment component of an OWTS other than the septic tank and soil treatment
area shall be equipped with access manholes with risers that extend to or above final
grade, located to permit periodic physical inspection, collection and testing of samples
and maintenance of all components and compartments.
3. Riser Lids
a. Each riser lid brought to the surface shall have a secure closing mechanism,
such as a lock, special headed bolts or screws, or sufficient weight to prevent
unauthorized access.
b. A local public health agency may require a secondary plug, cap, cover or screen
be provided below the riser cover to prevent tank entry if the cover is
unknowingly damaged or removed.
4. Components that require access for maintenance shall include but not be limited to
submerged bearings, moving parts, pumps, siphons, valves, tubes, intakes, slots,
distribution boxes, drop boxes, cleanouts, effluent screens, filters, inlet and outlet baffles,
aerators, treatment equipment and other devices.
5. Components shall be designed and constructed so that, when installed, they shall be
easily maintained, sampled, and serviced according to the manufacturer's
recommendations. Easy physical access to treatment components by maintenance
personnel and equipment shall be provided.
D. Plumbing Codes: Plumbing fixtures, building sewers, vents, sewer lines and other appurtenances
shall be designed, operated and maintained so as to comply with the minimum requirements of
the most recently revised locally enforceable plumbing code. In absence of a local plumbing
code, designs shall adhere to the Colorado Plumbing Code (3 CCR 720-1).
E. Electrical Equipment, If Used
1. All electrical work, equipment, and material shall comply with the requirements of the
currently applicable National Electrical Code as designated by the State Electrical Board
Rules and Regulations (3 CCR 710-1). A local State electrical permit may be required.
2. Electrical components shall be protected from moisture and corrosive gases.
F Indicators of Failure or Malfunctioning for Systems Utilizing Mechanical Apparatus: A signal
device shall be installed which will provide a recognizable indication or warning to the user that
the system or component is not operating or is operating but malfunctioning. This indication or
warning shall be a visual signal or an audible signal or both and shall be located in a centralized
area within visual and audible range of the system user. A signal or message may also be sent
remotely to a maintenance provider.
42
III ,irdFM:0111111.11 ,Mfi111151 1114qPiiiiiiSi11l is 11111
Reception#: 848421
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47 of 80 Rec Fee $0.00 Doc Fee 00 GARFIELD COUNTY CO
G. Sampling Access
43.8 Design Criteria — General
1. If sampling for testing or as a requirement for a permit will be required of effluent from a
component other than the soil treatment area, an accessible sampling point shall be
provided.
2. If sampling of the treated wastewater from the soil treatment area will be required for
testing or as a requirement for a permit, a monitoring well or wells shall be constructed.
Monitoring wells shall be located down gradient from the soil treatment area, accessible,
and provided with a properly securable cover at or above the ground surface. Monitoring
wells up gradient of the system may also be required. Lysimeters or other collection
devices under the soil treatment area may be used instead of a monitoring well if
approved by the local public health agency or other issuer of a permit.
H. Component Operating Instructions
1. The manufacturer of proprietary treatment units utilizing mechanical components shall
provide clear, concise written instructions covering the components which, when
followed, shall assure proper installation and safe and satisfactory operation and
maintenance.
2. If the OWTS uses public domain technology, the design engineer shall provide clear,
concise written instructions covering the components which, when followed, shall assure
proper installation and safe and satisfactory operation and maintenance.
Surface Activity: Activity or use on the surface of the ground over any part of the OWTS must be
restricted to that which shall allow the system to function as designed and which shall not
contribute to compaction of the soil or to structural loading detrimental to the structural integrity or
capability of the component to function as designed. During construction, equipment shall be
kept off of the ground surface above the soil treatment area and out of the excavation to prevent
compaction. If compaction occurs, the disturbed or compacted soil shall be re-evaluated and new
percolation tests may be performed to the disturbed or compacted soil and the system
redesigned if the parameters have changed.
J. Floodplains
1. New OWTS and replacement OWTS installed in a 100-year floodplain shall meet or
exceed the requirements of the Federal Emergency Management Agency and the local
emergency agency. Repairs of an existing system shall meet the requirements as
feasible. The system as approved by a local public health agency shall be designed to
minimize or eliminate infiltration of floodwaters into the system and discharge from the
system into the floodwaters.
2. No new or expanded OWTS shall be installed in a floodway designated in a 100-year
floodplain. For any system repair that may affect the floodway delineation, appropriate
procedures shall be followed including revision of the floodway designation, if necessary.
K. Business Commercial, Industrial, Institutional or Multi -Family Dwelling Wastewater Systems
1. An OWTS that will serve a business, commercial, industrial or institutional property, or a
multifamily dwelling shall:
a. Be designed by a professional engineer;
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43.9 Design Criteria - Components
b. Receive only such biodegradable wastes for treatment and distribution as are
compatible with those biological treatment processes as occur within the septic
tank, any additional treatment unit and the soil treatment area; and
c. Receive authorization by rule or a class V underground injection permit from the
United States Environmental Protection Agency (EPA) before an application for
an OWTS permit is approved if the system may receive non-residential
wastewater or is otherwise covered by the EPA underground injection control
program.
43.9 Design Criteria - Components
A. Tanks and Vaults
1. Watertightness
a. Septic tanks, vaults, pump tanks, other treatment components, risers and lids
shall not allow infiltration of ground water or surface water and shall not allow the
release of wastewater or liquids through other than designed openings.
b. Acceptable watertightness testing methods performed at a manufacturer's site or
in the field include water filling the tank or vacuum testing.
2. Tank Anchoring: In locations where ground water or floodwaters may cause instability
problems to the septic tank, vault, or other treatment unit in the OWTS due to flotation,
the tank, vault or unit shall be anchored in a manner sufficient to provide stability when
the tank is empty. Risers shall be included in the buoyancy calculations.
a. If a manufacturer provides recommendations for anchoring designs, they may be
used if they meet the conditions present at the site.
b. If a manufacturer does not provide recommendations for provisions to
compensate for buoyancy, or if the professional engineer chooses to provide
his/her own designs, the anchoring system design shall be prepared by the
professional engineer.
3. Identification and Data Marking: All tanks and treatment units shall be permanently and
legibly marked in a location for the purpose of inspection that is readily visible when
inspected before backfilling. The marking inscription shall include the following:
a. Name of manufacturer;
b. Model or serial number, if available;
c. Effective volume and unit of measure;
d. Maximum depth of earth cover and external loads the tanks is designed to resist;
and
e. Inlet and outlet identifications, if relevant.
B. Septic Tanks
1. The manufacturer shall provide sufficient information to demonstrate that the tank will
meet the design specification.
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43.9 Design Criteria - Components
2. Sizing Requirements:
a. Sizing for residential capacity for new installations shall be based upon the
number of bedrooms according to Table 9-1:
nk Size Based on Number of Bedrooms
Number of Bedrooms
Tank Capacity (gallons)
2 or 3
1,000
4
1,250
Each Additional
250
b. For multi -family and non-residential applications, a septic tank shall be sized to
permit detention of incoming wastewater design flows for a minimum of 48 hours.
c. For systems that remove toilet waste for separate treatment, tank capacity may
be less than 1,000 gallons, if it provides a minimum of 48 hours detention time.
d. Minimum tank size for new installations other than for a single-family residence is
400 gallons.
3. Testing of Septic Tank Watertightness
a. Testing of septic tanks must be performed and evaluated as specified in section
9 of ASTM C1227-12 (Standard Specification for Precast Septic Tanks) for
concrete tanks or in Standard IAPMO/ANSI Z1000-2007 (American Standards for
Prefabricated Septic Tanks) for other prefabricated septic tanks.
b. Each unit shall be inspected in the field for conditions that may compromise its
watertightness.
c. The inspection in the field shall be conducted by the local public health agency
and be performed after the tank installation but before backfilling.
d. If the inspection in the field indicates that the tank may be damaged or is not
watertight, the inspector may require that the tank be tested for watertightness by
the tank manufacturer or the system contractor.
4. Septic Tank Design and Dimension Criteria
a. A septic tank shall have two or more compartments or more than one tank may
be used in series. The first compartment of a two -compartment tank or the first
tank in a series shall hold no less than one-half of the required effective volume.
b. Inlet invert shall be at least two inches higher than the outlet invert.
c. inlet tee or baffle shall extend above the surface of the liquid at least five inches
and shall extend a minimum of eight inches below the liquid surface.
d. Outlet tee or baffle shall extend at least 14 inches below the outlet invert and, if
needed, be modified to accommodate an effluent screen. The outlet tee or baffle
that accommodates an effluent screen must be located so that the effluent
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43.9 Design Criteria - Components
screen has sufficient clearance to be removed through the access opening with a
riser in place.
e. The distance from the outlet invert to the underside of the tank top shall be at
least ten inches.
f. Liquid depth shall be a minimum of 30 inches and the maximum depth shall not
exceed the tank length.
g. The transfer of liquid from the first compartment to the second or successive
compartment shall be made at a liquid depth of between 35 and 40 percent of the
liquid depth measured from the liquid surface.
h. At least one access manhole no less than 20 inches across shall be provided in
each compartment of a septic tank.
A septic tank shall have a minimum of 25 square feet of liquid surface area and
have at least a six-foot separation between inlets and outlets. Septic tanks in
series, combined, shall have a minimum of 25 square feet of liquid surface area
and the sum of the distances between inlets and outlets of all tanks must be at
least six feet. The requirements for liquid surface area and separation between
inlet and outlet may be waived for tanks with less than 750 gallon effective
volume.
5. Concrete Septic Tank Structural Design
a. Concrete septic tanks shall comply with the structural design criteria of ASTM
C1227-12 (Standard Specification for Precast Septic Tanks).
b. The design for each tank model and size by each manufacturer must be certified
by a professional engineer as complying with these design and structural
requirements and the watertightness standard of this regulation.
c. Certification by a professional engineer must be submitted to the Division for
acceptance.
d. Tank slab lids or mid -seam tanks shall be sealed to be watertight.
e. Connections between tank and risers shall be sealed to be watertight.
6. Fiberglass, Fiberglass -Reinforced Polyester, and Plastic Tanks
a. All fiberglass, fiberglass -reinforced polyester, and plastic tanks shall meet the
minimum design and structural criteria of IAPMO/ANSI Z1000-2007 (American
Standards for Prefabricated Septic Tanks) and be certified by a professional
engineer as meeting these standards. The professional engineer certifying the
criteria must be registered or licensed in the United States, but need not be
registered in Colorado.
b. All tanks shall be sold and delivered by the manufacturer or manufacturer's
designated representative, preferably completely assembled. On -site tank
assembly will be allowed on an as -needed basis.
c. Tanks shall be structurally sound and support external forces as specified in the
standard referenced above when empty and internal forces when full. Tanks
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43.9 Design Criteria - Components
shall not deform or creep resulting in deflection of more than five percent in
shape as a result of loads imposed.
d. All tanks shall be constructed of sound, durable materials and not be subject to
excessive corrosion, decay, frost damage, or cracking.
e. All seams or connections including to risers shall be sealed to be watertight.
7. Metal tanks are prohibited.
C. Abandonment of Tank
1. A tank may be completely removed and the parts disposed of safely.
2. If the tank will remain in place:
a. The tank shall be pumped to remove as much waste as possible;
b. The bottom of the tank shall be broken so the tank neither floats nor fills with
water;
c. The top must be collapsed and the sides may be broken into the void;
d. The remaining void shall be filled with gravel, sand or compacted soil; and
e. The filled excavation will be graded to surroundings, allowing for settling.
3. The local public health agency may require abandonment of a tank that is deemed to be
a hazard.
D. Pipe Standards and Bedding Requirements:
1. Pipe Standards
a. All wastewater lines used in an OWTS shall be constructed of compatible pipe,
primer, bonding agent, and fittings.
b. Where unperforated plastic pipe and fittings are used for gravity flow, the
minimum wall thickness of the pipe shall conform to ASTM Standard D 3034 or
equivalent or greater strength. Schedule 40 pipe is preferred.
c. Perforated distribution pipe surrounded by rock within a soil treatment area shall
have a minimum wall thickness and perforations conforming to ASTM Standard
D 2729 or equivalent or greater strength. Corrugated polyethylene pipe with
smooth interior that meets ASTM F405 or AASHTO M252 specifications or
equivalent may be used.
d. Schedule 40 or pipe of equivalent or greater strength shall be used for the
placement of piping under driveways or roadways and in instances where sewer
line setback distances are granted a variance for any reason.
e. Tile pipe, open joint pipe, and cast iron pipe must not be used in an OWTS.
f. Pressure pipe must be rated for the intended use to accommodate pump
discharge pressure.
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43.9 Design Criteria - Components
2. Bedding: All system piping, except for distribution laterals within the soil treatment area,
shall be bedded with select material before final inspection by the local public health
agency. Select bedding material shall consist of loose, granular material, free from
stones, clods, frozen soil, or other deleterious material. Select material may consist of on -
site job -excavated or imported material. Bedding material must be mechanically
compacted to support piping.
E. Distribution Box: A distribution box, if used, shall be of sufficient size to distribute effluent equally
to the lateral lines of a trench or absorption bed system. The box shall be constructed with the
inlet invert at least one inch above the level of the outlet inverts. Flow equalizers or similar
devices shall be used to adjust the flow between lines. Access to the box shall be provided with a
manhole riser with access lid at or above grade if the top of the box does not reach final grade.
F. Drop Box: In sequential or serial distribution, a watertight box may be used to transfer the
effluent to the following trench when the effluent in a trench has received the designed level for
overflow to the next trench. A drop box shall have a riser at or above final grade, if the top of the
drop box does not reach final grade. Outlet lines in sequential distribution shall be designed and
installed so that they may be capped off for resting periods.
G. Step-down/Relief Line: In sequential or serial distribution, an unperforated pipe may be used to
transfer the effluent to the following trench when the effluent in a trench has received the
designed level for overflow from that trench.
H. Wastewater Pumping and Dosing Siphon Systems
1. Pumps
a. Non -clog pump opening shall have at least two-inch diameter solids handling
capacity where raw wastewater is pumped. A pump opening shall not have more
than 3/4-inch diameter solids handling capacity if previously settled effluent is
pumped.
b. Pumps must be certified to the applicable UL or CSA electrical safety standard,
bear the seal of approval of CSA, UL or an equivalent testing program and be
constructed of corrosion resistant materials.
c. Grinder pumps must also be certified to NSF/ANSI Standard 46 and bear the
seal of approval of the NSF or equivalent testing and certification program.
2. Floats and Switches
a. Automatic liquid level controls must be provided to start and shut off pumps at a
frequency or level specified in the design.
b. Floats must be mounted on a stem separate from the pump discharge piping to
allow for removal, adjustment, and replacement of the float without removing the
pump.
c. Float switches must be certified to the applicable UL or CSA electrical safety
standard, bear the seal of approval of CSA, UL or an equivalent certification
program and be constructed of corrosion resistant materials.
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43.9 Design Criteria - Components
3. Location of Pump or Siphon
a. A pump may be, or a siphon shall be, installed in a separate tank following the
septic tank and be of sufficient volume to allow pump or siphon cycling
commensurate with the design capacity. The use of a three -compartment septic
tank, sized to provide effective volume in the first two compartments with the
pump in the third compartment, is acceptable.
b. The second compartment of the septic tank shall not be used as the pump tank
unless it can be demonstrated to the satisfaction of the local public health agency
that the minimum 48-hour detention time will not be decreased and the pump is
screened or provided with an approved filtering device to assure that only liquid
effluent will be discharged.
4. Pump or Siphon Discharge Piping
a. The discharge line from the pumping or siphon chamber shall be protected from
freezing by burying the pipe below frost level or sloping the pipe to allow it to be
self -draining. Drainage shall be provided through the bottom of the pump or
through a weep hole located in the discharge line prior to exiting the tank.
b. The pump discharge piping shall have a quick disconnect that is accessible
within the riser to allow for easy pump access and removal.
c. The pipe shall be sized to maintain a velocity of two or more feet per second.
d. Automatic air/vacuum release valves shall be installed at high points in the
pressure line where necessary to prevent air or vacuum locking and allow self
draining of the lines.
5. Access
a. The pump or dosing system tank, chamber, or compartment shall have a
minimum 24-inch diameter access riser, made of corrosion -resistant material,
extending to or above ground level.
b. The access riser must have a watertight connection to the pump or dosing
chamber/compartment to prevent infiltration or exfiltration.
6. Splice Box
a. Splice boxes shall be located outside the pump system access riser and be
accessible from the ground surface.
b. No wire splices shall be made inside the tank, dosing chamber or riser. Wire
splicing shall be completed with corrosion -resistant, watertight connectors.
7 Controls
a. The pump system shall have an audible and visual alarm notification in the event
an excessively high water condition occurs.
b. The pump shall be connected to a control breaker separate from the high water
alarm breaker and from any other control system circuits.
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43.10 Design Criteria— Soil Treatment Area
c. The pump system shall have a switch so the pump can be manually operated.
d. The pump system for pressure dosing and higher level treatment systems shall
have a mechanism for tracking either the amount of time the pump runs or the
number of cycles the pump operates.
e. Control panels shall be UL listed.
Effluent Screens
1. Effluent screens shall be installed in all septic tanks in new installations and repairs
where the septic tank is replaced.
2. If a pump or dosing siphon is used to remove septic tank effluent from the final
compartment of the septic tank, an effluent screen must be provided prior to the pump or
siphon inlet. A pump vault equipped with a filter cartridge may be considered equivalent
to an effluent screen preceding the pump.
3. The effluent screen shall be cleaned at manufacturer -recommended intervals, or more
often, if use patterns indicate.
4. An alarm may be installed on an effluent screen indicating need for maintenance.
J. Grease Interceptor Tanks
1. All commercial food service facilities and other facilities generating fats, oils and greases
in their waste must install a grease interceptor tank.
2. Grease interceptor tanks shall treat only those portions of the total wastewater flow in
which grease and oils are generated.
43.10 Desiqn Criteria— Soil Treatment Area
A. The size and design of the soil treatment area shall be based on the results of the site and soil
evaluation, design criteria, and construction standards for the proposed site and OWTS selected.
B. At proposed soil treatment area locations where any of the following conditions are present, the
system shall be designed by a professional engineer and approved by the local public health
agency:
1. The soil classifications are Types 0, 3A, 4, 4A, and 5 and Treatment Levels TL2, TL2N,
TL3, and TL3N as specified in Table 10-1 of this regulation;
2. The maximum seasonal level of the ground water surface is less than four feet below the
bottom of the proposed absorption system;
3. A restrictive layer exists less than four feet below the bottom of the proposed absorption
system;
4. The ground slope is in excess of thirty percent; or
5. Pressure distribution is used.
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43.10 Design Criteria— Soil Treatment Area
C. Calculation of Infiltrative Surface of Soil Treatment Area
1. The infiltrative surface of a trench or bed receiving any treatment level of effluent is only
the bottom area. No sidewall credit is allowed except in deep gravel trenches and
seepage pits that are permissible in repairs.
2. Long-term acceptance rates (LTARs) are shown in Table 10-1.
3. Factors for adjusting the size of the soil treatment area are in Tables 10-2 and 10-3.
4. The required area for a soil treatment area is determined by the following formula:
Soil Treatment Area in square feet required = Design Flow (in gallons per day)
LTAR (in gallons per day per square foot)
a. Adjusted Soil Treatment Area = Required Soil Treatment Area x Size Adjustment
Factor(s).
b. Size adjustment factors for methods of application are in Table 10-2.
c. Size adjustment factors for types of storage/distribution media are in Table 10-3.
d. A required soil treatment area receiving TL1 effluent may be multiplied by one
size adjustment factor from Table 10-2, Table 10-3, or both.
e. A soil treatment area receiving TL2, TL2N, TL3, or TL3N effluent must be
pressure dosed. The distribution media in Table 10-3 may be used for
distribution of higher level treatment system effluent, but an additional reduction
factor from Table 10-3 shall not be used.
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Design Criteria— Soil Treatment Area
Long-term Acceptance Rate (LTAR);
Gallons per day per square foot
Treatment Treatment
Level 31 Level3N'*
Minimum 2-foot deep unlined sand filter required2
•t
O
r-
CO
G
0.80
O
6
0.30 a
N
O
r-
O
1.40 1
O
COD
O
m
O
inco
O
O
N
O
1 0.15
Treatment
Level 2N'
La N
W
O
r-
O
EL)
[7
O
M
O
IV
C
v-
6
Treatment
Level 21
N
r-
8
0
O
O
so
6
Q
O
I 0.30
n
0
a
O
Treatment
Level 11
Minimum
3-foot deep
unlined
sand filter
req u ired2
co
0
us
0
10
O
0.35
co
O
0.20
T
O
co
O
Soil Type, Texture, Structure and Percolation Rate Range
Percolation
Rate (MPI)
V
V
IA
N
cb
V
N
41-60
1;
m
CA
ti
CV
w
CO.-
4.
N
7 0
en 4,7 0
C
O
O
2 (Moderate)
3 (Strong)
1 (Weak)
Massive
N
r es
2
2,
USDA Soil
Structure -
Shape
f
1
_!
lO Y >
d y CO O 0 N
a °° c?
(auou) 0
tIO
'N9 'lid
PR, BK,
GR
SC
0 O
PR, BK,
GFt
Y
m
(+� O
i'
Q
USDA Soil Texture
Soil Type 1 with more
than 35% Rock (>2mm);
Soil Types 2-5 with more
than 50% Rock (>2mm)
Sand, Loamy Sand 1
Sandy Loam, Loam, Silt
Loam
Sandy Loam, Loam, Silt
Loam
Sandy Clay Loam, Clay
Loam, Silty Clay Loam
Sandy Clay Loam, Clay
Loam, Silty Clay Loam
Sandy Clay, Clay, Silty
Clay
Sandy Clay, Clay, Silty
Clay
Soil Types 2-4A
0
O
T
N
N
V)
g
4
CD
Shaded areas require system design by a professional enginee
Treatment levels are defined in Table 6-3.
Unlined sand filters in these soil types shall provide pathogen removal. Design shall conform to section 11.C.2.c, Unlined Sand Filters
.111 ElialVIVAPis''ti g1ii!DI'r31iWierillik:,,1WY) II III
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43.10 Design Criteria— Soil Treatment Area
D. Allowable Soil Treatment Area Reductions and Increases:
1. The soil treatment area size determined by dividing the design flow rate by the long-term
acceptance rate may be adjusted by factors for method of treatment, soil treatment area
design, and type of distribution media.
2. For the purpose of the table, a "baseline system," i.e. adjustment factor of 1.00, is
considered to be Treatment Level 1 (TL1) applied by gravity to a gravel -filled trench.
3. The maximum reduction from all combined reductions including higher level treatment
shall be no greater than 50 percent of the baseline system required for a soil treatment
area.
4. Reductions for use of the higher level treatment categories listed in Table 10-1 shall only
apply provided the system is inspected and maintained as specified in the requirements
of section 14.D., Permitting and Oversight of Maintenance for Soil Treatment Area
Reductions and Vertical and Horizontal Separation Distance Reductions Based on Use of
Higher Level Treatment.
Table 10-2 Size Adjustment Factors for Methods of Application in Soil Treatment Areas
Table 10-3
tins Treatment Levels 1, 2, 2N, 3 and 3N Effluent
Type of Soil
Treatment Area
Method of Effluent Application from Treatment Unit
Preceding Soil Treatment Area .
Gravity
Dosed (Siphon or
Pump)
Pressure Dosed
Trench
1.0
0.9
0.8
Bed
1.2
1.1
1.0
Size Adjustment Factors for Types of Distribution Media in Soil Treatment Areas
Accepting Treatment Level 1 Effluent
Type of Soil Treatment
Area
Type of Storage/Distribution Media Used in Soil Treatment Area
Rock or Tire Chips
Manufactured Media
Other Than Chambers
Chambers
Trench or Bed
1.0
0.9
0.7
E. Design of Distribution Systems
1. General
a. The infiltrative surface and distribution lines must be level.
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43.10 Design Criteria— Soil Treatment Area
b. The infiltrative surface must be no deeper than four feet unless adequate
treatment at a deeper level can be demonstrated and is approved by the local
public health agency. The depth will be measured on the downslope side of the
trench or bed.
c. Trenches must follow the ground surface contours so variations in infiltrative
surface depth are minimized. Beds must be oriented along contours to the
degree possible.
d. Pipe for gravity distribution must be no less than three inches in diameter.
e. A final cover of soil suitable for vegetation at least ten inches deep must be
placed from the top of the geotextile or similar pervious material in a rock and
pipe system, chamber, or manufactured media up to the final surface grade of
the soil treatment area.
f. Following construction, the ground surface must be graded to divert stormwater
runoff or other outside water from the soil treatment area. The area must be
protected against erosion. Subsurface drains upslope of the soil treatment area
may be installed to divert subsurface flow around the area.
g. Backfilling and compaction of soil treatment areas shall be accomplished in a
manner that does not impair the intended function and performance of the
storage/distribution media and soil and distribution laterals, allows for the
establishment of vegetative cover, minimizes settlement and maintains proper
drainage.
2. Distribution Lines
a. Distribution between lines in a soil treatment area must be as even as possible.
Uneven settling of portions of the distribution system following construction must
be addressed by provisions in the design to adjust flows between lines.
b. Distribution lines longer than 100 feet may be pressure dosed or the application
of the effluent shall be at the center of the line. These systems must be designed
by an engineer.
c. The end of a distribution pipe must be capped, unless it is in a bed or trenches in
a level soil treatment area, where the ends of the lines may be looped.
d. Inspection Ports
(1) An inspection port accessible from ground surface must be installed at
the terminal end of each line. The bottom of the inspection port tube
must extend to the infiltrative surface and not be connected to the end of
the distribution pipe. Inspection ports in chambers may be installed
according to manufacturer's instructions if the infiltrative surface is visible
or can be measured from the inspection port.
(2) Additional inspection ports connected to distribution pipes may be
installed.
(3) An inspection port shall be installed at the initial end of each line.
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43.10 Design Criteria— Soil Treatment Area
(4) The top of inspection ports may be below the final grade of the surface if
each has a cover at the surface such as a valve box for a lawn irrigation
system.
e. Trenches
(1) Trenches must be three feet wide or less.
(2) The separating distance between trenches must be a minimum of six
feet sidewall-to-sidewall.
(3) Perforated distribution pipe used in a trench must be as close to the
center of the trench as possible.
(4) Perforations must be oriented downward unless pressure distribution is
used and provision for pipe drainage is included.
f. Beds
(1) Maximum width for a bed must be 12 feet, unless the bed receives
effluent meeting Treatment Level 2 quality or better.
(2) The separating distance between beds must be a minimum of six feet
sidewall-to-sidewall.
(3) The separating distance between parallel distribution lines in an
absorption bed must not exceed six feet and a distribution line must be
located within three feet of each sidewall and endwall of the absorption
bed.
g. Serial and Sequential Distribution:
(1) A serial or sequential distribution system may be used where the ground
slope does not allow for suitable installation of a single level soil
treatment area unless a distribution box or dosing chamber is used.
(2) The horizontal distance from the side of the absorption system to the
surface of the ground on a slope must be adequate to prevent lateral
flow and surfacing.
(3) Adjacent trenches or beds must be connected with a stepdown/relief line
or a drop box arrangement such that each trench fills with effluent to the
top of the gravel or chamber outlet before flowing to succeeding
treatment areas.
3. Storage/Distribution Media
a. Rock and Pipe
(1) The pipe must be surrounded by clean, graded gravel, rock, or other
material of equal efficiency which may range in size from 1/2 inch to 2
1/2 inches. At least six inches of gravel, rock or other material must be
placed below the pipe. The gravel, rock or other material must fill the
trench around the pipe and at least two inches above the top of the
distribution pipe.
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11111learlil'ilf,4111 'eiEr10,1:i'Iill'riIr:h'N10.11,FY41'' 11111
Reception 848421
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43.10 Design Criteria— Soil Treatment Area
(2) The top of the placed gravel or such material used must be covered with
non -woven permeable geotextile meeting a maximum thickness rating of
2.0 ounces per square yard or equivalent pervious material. An
impervious covering must not be used.
b. Tire Chips
(1) The pipe may be surrounded with clean, uniformly -sized tire chips.
(2) Tire chips must be nominally two inches in size and may range from 1/2
inch to a maximum of four inches in any one direction.
(3) Wire strands must not protrude from the tire chips more than 0.75
inches.
(4) Tire chips must be free from balls of wire and fine particles less than two
mm across.
(5) The top of the tire chips used must be covered with non -woven
permeable geotextile meeting a maximum thickness rating of 2.0 ounces
per square yard or equivalent pervious material. An impervious covering
must not be used.
c. Chambers
(1) Chambers must be installed with the base on the infiltrative surface.
(2) Installation must be according to manufacturer's instructions.
(3) Effluent may be distributed by gravity or pressure dosing.
d. Manufactured Media
(1) Manufactured media must be installed with the base on the infiltrative
surface.
(2) Installation must be according to manufacturer's instructions.
(3)
Effluent may be applied by pressure distribution only if the manufacturer
specifies suitability of the product for that use.
e. Pressure Distribution
(1) Design of pressure distribution systems must include:
(i) Dose size and frequency for flows and soil or media long-term
acceptance rate;
(ii) Pipe diameter and strength requirements;
(iii) Orifice size and spacing; and
(iv) Distal pressure head.
(2) Cleanouts must be installed at the end of each line.
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43.10 Design Criteria— Soil Treatment Area
f. Driplines
(1) The infiltrative surface area must be calculated using the long-term
acceptance rate for the site or a more conservative value if
recommended by the manufacturer.
(2) Driplines must be installed on manufacturer's spacing recommendations.
(3) Drainback must be provided for all drip lines, pipes and pumps.
(4) Provisions must be made to minimize freezing in the distribution lines,
driplines, relief valves, and control systems.
(5)
Provisions must be made for backflushing or other cleaning.
F. Alternating and Sequencing Zone Systems
1. Alternating Systems
a. An alternating system must have two zones that must be alternated on an annual
or more frequent basis.
b. Each section must be a minimum of 50 percent of the total soil treatment area.
Size adjustment factors for methods of effluent application or type of distribution
media shall not be allowed.
c. A diversion valve or other approved diversion mechanism may be installed on the
septic tank effluent line allowing soil treatment area sections to be alternated.
d. The diversion mechanism must be readily accessible from the finished grade.
2. Sequencing Zone Systems
a. Sequencing zone systems have more than two soil treatment area sections that
are dosed on a frequent rotating basis.
b. Where soil conditions are similar between the sections, each section area shall
be the same size. If soil conditions are such that long-term acceptance rates are
different, each section may be sized for the same dose, but different long-term
acceptance rates.
c. An automatic distribution valve must be used.
d. Dosing of each system must be evaluated by the design engineer based on
projected daily flow rates, number of zones, and soil types.
G. Dosing: Dosing may be used for soil treatment area distribution. The dose must be sized to
account for the daily flow and the dosing frequency.
H. Soil replacement must be permitted to bring the soil within the requirements of suitable soil.
Added soil must meet the specifications of sand filter media, as specified in section
43,11.C.2.a.(1). All added soil must be completely settled prior to installation of components as
specified and approved by the design engineer. The loading rate for sand filters must be used.
Pressure distribution must be used.
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43.10 Design Criteria— Soil Treatment Area
Repairs
1. When space is not available or if there are other site limitations that preclude other soil
treatment area options for OWTS repairs, wide beds, deep gravel trenches, and seepage
pits may be considered for repairs only. Other options are vaults or higher level
treatment systems, if the local board of health permits them.
2. Wide Beds: For repairs, beds may be wider than 12 feet without being required to
receive effluent meeting Treatment Level 2 quality or better.
3. Deep Gravel Trenches
a. The length of an absorption trench or bed may be calculated by allowance for the
sidewall area of additional depth of gravel in excess of six inches below the
bottom of the distribution pipe according to the following formula:
Adjusted Length = L x (W+2)
(W+1+2D)
Where:
L = length of trench prior to adjustment for deep gravel
W = width of trench or bed in feet
D = additional depth in feet of gravel in excess of the minimum required six
inches of gravel below the distribution pipe
b. Maximum allowable additional depth is five feet.
c. Percolation tests and soil profile hole or soil profile excavation test pit evaluations
must be performed at the proposed infiltrative surface depth.
d. The reduction in field size area with the use of chambers must not be applied to
deep gravel systems.
4. Seepage Pits
a. For repairs, potential for risk to public health and water quality may be evaluated
by the local public health agency. If risk is low in the determination of the local
public health agency, a seepage pit without higher level treatment may be used.
b. If the risks are not low, higher level treatment of at least TL2 must be attained
prior to discharge to these systems for final disposal.
c. A seepage pit shall consist of a buried vertical cylinder with holes in the wall.
(1) Pits must be provided with both vertical sidewall and top supporting
structural concrete or other material of equal structural integrity.
(2) The excavation must be larger than the cylinder by at least 12 inches on
each side.
(3) The over -excavated volume must be filled with rock ranging in size from
1/2 inch to 2 1/2 inches.
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Design Criteria — Higher Level Treatment Systems
(4) The capacity of the pit must be computed on the basis of long-term
acceptance rates determined for each stratum penetrated. The weighted
average of the results must be used to obtain a design figure.
(5) Soil strata in which the percolation is slower than 30 minutes per inch
must not be used for absorption or seepage. These strata must not be
included in the weighted average to determine the long-term acceptance
rate.
(6) The infiltrative surface of the pit is the vertical wall area (based on dug
perimeter) of the pervious strata below the inlet plus the bottom area
inside the vertical cylinder.
d. Pits must be separated by a distance equal to three times the greatest lateral
dimension of the largest pit. For pits over 20 feet in depth, the minimum space
between pits must be 20 feet.
e. The construction of new seepage pits for the treatment and dispersal of on -site
wastewater on new sites is prohibited unless:
(1) The seepage pit is designed by a professional engineer; and
(2) The design includes higher level treatment of at least TL2.
5. Vaults
a. The allowable use of vaults for repairs in a local jurisdiction is determined by the
local board of health.
b. Criteria for vaults are in section 12.D. of this regulation.
6. Higher Level Treatment Options
a. Reduction in required soil treatment area for repairs is possible with higher level
treatment.
b. Design criteria for higher level treatment systems are in section 11.
43.11 Design Criteria — Higher Level Treatment Systems
A. General
1. Higher level treatment systems must be designed by a professional engineer.
2. Higher level treatment systems may be public domain technology systems or proprietary
systems.
a. Public domain technology systems must be designed, installed and maintained
according to established criteria and additional criteria established by the local
public health agency. When design criteria are not specifically provided in this
regulation, the criteria used in the design must be from a reference commonly
used as an industry standard and the criteria must be cited in the design.
59
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Schematic for Permit
and Construction
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BUILDING
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PROPERTY LINE
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Graphic Scale
0 12.5 25
In Feet: 1" = 50'
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LOT LINE
LOT 7A.
BUILDING
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LIST OF DRAWINGS
SHEET DESCRIPTION
1
2
3
4
TITLE SHEET
LOT 6 OWTS
LOT 7 OWTS
DETAILS
V/C/N/TY MAP
NO SCALE
ACM
118 West Sixth Street, Suite 200
Glenwood Springs, CO 81601
970.945.1004 www.sgm-inc.com
Garfield County, Colorado
Daniels Residence
S 22, T6N, R 3\A/, Rifle, CO
OWTS Design and Details
GRAVITY SYSTEM
Lots 6 & 7, Title Sheet
2019-292.001
Drawn by:
JSS
Date:
07/03/19
QC:
PE:
JSS
File: Daniels -BM
Of
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4