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HomeMy WebLinkAbout1.12 Weed management planSouth Parachute 20"-8"-6" Pipeline Extension Integrated Vegetation and Noxious Weed Management Plan Garfield County Special Use Permit Condition Prepared for: EnCana Oil & Gas (USA), Inc. Prepared by: WestWater Engineering (In coordination with Wagon Wheel Consulting) October 2005 Introduction The South Parachute Pipeline Extension begins at a point south of the Colorado River near Parachute in Garfield County, Colorado. The beginning point is located on High Mesa in the SE1/4SE'/4, Section 35, T7S, R96W, 6th PM. It runs northeasterly to a location in the NE 1 /4NE 1 f4, Section 15, Township 7 South, Range 95 West of the 6th Principal Meridian. The project encompasses a right-of-way 100 feet wide approximately 49,000 in length. It is located on private and public lands administered by the Glenwood Springs Field Office of the Bureau of Land Management. The project includes an easterly extension that 'T's off the main extension at a point in the NW 1 f4S W I/4 Section 29, T7S, R95W, 6th PM and runs easterly up Dry Creek to a point in the NE1f4SWI/4 of Section 27, T7S, R95W, 6th PM (Figure 1). Most of the extension occurs in existing pipeline or road right-of-way and will re -disturb previously disturbed lands in various stages of rehabilitation. Some introduced and native grasses, forbs and a few native shrubs are found in the existing right-of-way. New disturbance will occur to some previously undisturbed pinyon/juniper woodlands, Gambel oakbrush, and big sagebrush shrub lands near the western end of the extension. Some weed -free private pasture with existing pipeline also will be re -disturbed, Site Inspection and Survey A site inspection was conducted by WestWater biologists on October 17 and 18, 2005. The right-of-way includes infested as well as a few weed free plant communities. Listed noxious weeds are found in the majority of the existing right-of-way. Actively growing rosettes and senescent, seed -bearing flowering stalks can be found in abundance. Some adjoining private agricultural pastures are mostly weed free. Some recently burned range land, mostly BLM, but also some private surface are lightly infested with Garfield County noxious weeds but heavily infested with cheatgrass and field bindweed. These areas appear to be subject to heavy grazing by cattle. Amount of Infested Land Needing Treatment The right-of-way and new eastern extension length totals nearly 49,000 feet and at 100 feet wide affects approximately 112.5 acres. The amount of currently infested land is estimated to be a minimum of 70% of the total affected area or about 79 acres. Some of the listed noxious weed species, e.g. chicory, are very low incidence and confined to a few individual plants near or on the right-of-way. Others such as musk thistle are common. Most infestations are light or low density, but some hotspots with heavy or dense stands are present (see Photo 1). Targeted Noxious Weeds and Control Methods Table 1 lists the Garfield County Noxious Weed Species known to be present at the site. This information will facilitate monitoring and control by EnCana field staff. Table 1. Garfield County Listed Noxious Weeds in or very near Pipeline Extension. Common Name*/ Symbol Scientific Name Type** Control Methods Common Burdock ARM1 Archly'? minus B Re -seed with aggressive grasses, cut or dig rosettes and bolting; plants, herbicides. Thistle, Musk CANU Carduus nutans B Till or hand grub in the rosette stage, mow at bolting or early flowering; apply seed head & rosette weevils, leaf feeding beetles, andlor herbicides in rosette stage. Knapweed, Russian ACRE3 Centaurea repens P Re -seeding disturbed sites with fast growing grasses, herbicide in fall (Curtail recommended), al lelopathic — tillage may be necessary Chicory CLIN Ciclrorium intybas P Mowing can reduce infestation, plant competitive grasses, herbicides work best on rosettes, Thistle, Canada CIAR4 Cirsium aruense Re -seeding with competitive plants necessary, mowing every 2 weeks over 3 growing seasons, mowing followed by fall herbicide application, beetles, herbicides in late summer or fall, combination of treatments necessary. Thistle, Bull CiVU C. vulgare B Weevils and gall flies, controlled grazing by goats and horses, hand grubbing, tillage or herbicides in rosette stage, repeated mowing at bolting stage Houndstongue CYOF Cynoglossum offlcinale B Re -seed with aggressive grasses, remove at flowering or early seed, or apply herbicides at pre -bud or rosette stage. Russian olive ELAN Elaeagnus angusti olia Seedlings and sprouts easily hand -pulled when the soil is moist. Once established, cut -stump herbicide treatment most effective. Most non -chemical methods for the control of stands (bulldozing, mowing, brush -cutting) are not effective in the long-term, unless all re -spouts are continually cut and removed, or otherwise treated, for many consecutive years Thistle, Scotch ONAC Onopordunr acanlhium Biennial; tillage, hand grubbing, herbicides in rosette stage, mowing at bolting stage Salt cedar TARA Tamarix ramosissima p Burning is not recommended; repeated or historic flooding of hottomlands to prevent seedling establishment; hand pulling seedlings; spray herbicides on basal portion of stems of young, smooth barked plants, cut larger plants and treat cut stumps within 30 minutes with concentrated herbicide plus an adjuvant (remove all stems from site after cutting - they will resprout if in contact with soil); shade intolerant - promote growth of native Table 1. Garfield County Listed Noxious Weeds in or very near Pipeline Extension. Common Name*/ Symbol SeiendfrcName Type** Control Methods riparian species that will shade out the tamarisk; beetles and mealy bug biological controls not available on Colorado River drainage at this time. *State of Colorado. 2000. Colorado Rev'sed Statute 35-5-5. **A - Annual, B - biennial, P — perennial Photo 1: Heavy Musk Thistle Infestation on Existing R -O -W. View looking northwesterly showing cattle and Off Road Vehicle t►aiil in foreground. 311311i 4V1 J 3Sli[ Two species included on the State of Colorado "C" list at 8CCR1203-19, Convolvulus arvensis, field bindweed (COAR4) and Bromus tectorum, downy brome or cheatgrass (BRTE), while common on or near existing right-of-way are not fisted by Garfield County. Due to ownership, ecological perturbations (the large rangeland fire previously described) and biology of cheatgrass and field bindweed, it is not practical or recommended by WestWater biologists for treatment to be extended to these two species within the affected right-of-way. Treatment of these species is not likely to be effective unless a coordinated integrated vegetation and noxious weed plan including the lands adjoining the pipeline alignment is implemented. A third State of Colorado "C" list noxious weed species, Verbascum thapsus, common mullein (VETH), is found in spots on the right-of-way near Garfield County listed noxious weeds (Table 1) and could reasonably be expected to be controlled during treatment recommended for those species. The following tables summarize the most effective treatment strategies for noxious weeds, depending upon their growth habits. Table 2 includes annuals and biennials, and Table 3 is for perennial species. Table 2. Treatment Strategies for Annual and Biennial Noxious Weeds Target: Prevent Seed Production 1. Hand grub (pull), hoe, till, cultivate in rosette stage and before flowering or seed maturity. 2. Chop roots below soil level. 3. Treat with herbicide in rosette or bolting stage, before flowering. 4. Mow biennials after bolting stage, before seed set. Mowing annuals may not prevent flowering. Table 3. Treatment Strategies for Perennials Target: Deplete nutrient reserves in root system, prevent seed production 1. Allow plants to expend as much energy from root system as possible, do not treat when first emerging in spring but allow growth to bud/bloom stage. 2. Herbicide treatment at bud to bloom stage or in the fall. In the fall plants draw nutrients into the roots for winter storage. Herbicides wilt be drawn down to the roots more efficiently at this time. if the weed patch has been present for a long period of time, another season of seed production is not as important as getting the herbicide into the root system. Spraying in the fall will kill the following year's shoots, which are being formed on the roots at this time. 3. Mowing usually is not recommended because the plants will flower anyway; seed production may be reduced, however. Many studies have shown that mowing perennials and spraying the re -growth is not as effective as spraying without mowing. Effect of mowing is species dependent; therefore, it is imperative to know the species and its biology. Recommendations Revegetation. It is recommended that disturbed areas be re -seeded with the following seed mix, or a Garfield County/BL.M approved mix: Table 4. Recommended Seed Mix for Treating Facility Scientific Name Common Name Application Rate Lbs PM/acre Pascopyrum smithii Western wheatgrass 4 Etyma lanceolatus lanceolatus Thickspike wheatgrass 3 I:lymus trachycaulus trachycurdus Slender Wheatgrass 3 Pseudoroegneria spicata spicata thuebunch wheatgrass 2 Achnatherum hyrenoides Indian ricegrass 1 Airiplex canescans Fourwing saltbrush 3.5 Astragalus cicer Cicer milkvetch 1 Sanguisorba minor Small Burnett 0.75 Total 16.25 Seed should be applied by broadcasting at an application rate of approximately 45-seeds/square foot onto a roughened surface, followed by harrowing to incorporate seed into the soil at a depth of VI to 2 inches. Re -seeding may be required if future monitoring indicates lack of adequate germination and establishment. Monitoring. Monitoring for targeted weeds should be performed on a weekly basis beginning at spring green -up and continuing through the growing season. Monitoring by qualified personnel should be conducted using Table 5 as a general guide to key plant growth periods and best control periods. As of October 17 and 18, 2005, no noxious weeds were found in portions of the right-of-way located in undisturbed pinyon/juniper woodlands, in agricultural fields receiving intensive agricultural practices, and in the Gambel oakbrush dominated portions of the extension running easterly up Dry Creek. These relatively weed free portions of the alignment should also be monitored for noxious weed invasion. Mechanical.. Seed -producing plants should be cut, bagged, and disposed of in a licensed landfill as soon as practical and if possible before disturbance. Observed weeds, particularly thistle rosettes, should be controlled when possible and practical first by mechanical means, primarily hand grubbing or pulling. Control of listed species in nearby disturbed areas is recommended to reduce the risk and rate of infestation in the affected right-of-way. Chemical. Spot treating will be necessary in and should include areas immediately adjacent to the right-of-way. Chemicals typically used include synthetic auxin growth regulators (e.g., 2,4D; Tordon, l3anvel, and Garton), EPSP synthase inhibitors (e.g., glyphosate) or a mix of these. In all cases, the certified applicator shall deem which chemical(s) and at what concentration(s) shall be used at the time of application. However, it is anticipated the aforementioned classes of chemicals will be first choice of most Certified Applicators or Qualified Supervisors. We recommended a private contractor be engaged to conduct the weed control and monitoring, or that a company representative with weed identification capabilities and pesticide application knowledge (preferably with a certified applicator's license) be assigned this function. Additional Information: Table 5 is a guide to timing of key biological processes and the best time for control of the subject species on an annual bask. Species Houndstongue Knapweed, Russian Tamarisk* Thistle, Bull - 1st yr Thistle, Bull - 2nd yr Thistle, Canada Thistle, Musk- 1st yr Thistle, Musk - 2nd Yr Thistle, Scotch Chicory Russian Olive Common burdock Noxi Table 5. Annual Biology Calendar of Selected Weeds for EnCana Oil & Gas (USA) Inc. South Parachute Pipeline Extension Integrated Vegetation and Noxious Weed Management Plan Type* Jan Feb March April May June July Aug Sept Oct Nov Dec B rosettes —> prebud flowering - seed set germination —> --> --> C P emerges —> flowering --> --> regrowth —> P semi- —> leaves flowering &seed growth flowering & seed set dormancy emerge set B germination rosettes --> .-> --> --> --> --> --> senescence & semi - dormancy B --> --> --> —> bolting flowering seed set--> —> —> rosettes P rosettes --> —> flowering seed set regrowth --> B germination rosettes --> --> --> --> --> --> 8 rosettes --> --> —> bolt flowering seed set --> B rosettes --> --> --> --> bolting flowering seed set germination - rosettes B germination -rosettes bolting flowering P germination B germination rosettes bolt flowering — seed set bud stage Toadflax, Yellow P growth flowering - seed set A = annual; WA = winter annual; B = biennial; P = perennial; CP = creeping perennial Shaded areas indicate best control timing. *Tamarisk control can be done at any time of year, but is easier when leaves are absent and weather is cooler. 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