Bullock Draw reservoir is a smaller 98-acre fishery managed by the NER DWR aquatics section. Water rights were purchased from Ouray Park Irrigation Company to help make this a sustainable fishery and prevent complete irrigation drawdowns. At some point, Eurasian watermilfoil (EWMF) entered the system and took over the reservoir. Fishing from shore is very difficult, and launching a boat is nearly impossible during peak fishing seasons. EWMF has made the reservoir an unstable fishery and habitat for waterfowl. We need to remove EWMF at its source to prevent further contamination in the drainage.

1) Acquire funding to purchase herbicide and administer a lake-wide treatment for EWMF at Bullock Draw Res, the canal that connects it to Cottonwood Res, and the inlet of Cottonwood Res in July/August of 2025. 2)Monitor the success of the treatment and do spot treatments if necessary.

EWMF in Bullock Draw presents multiple problems, one for the ability of anglers to use the fishery, and the second is it provided an overabundance of nonnative habitat that supports many unwanted rough fish in the system (white suckers, carp), and hinders waterfowl from using the reservoir as habitat by getting tangled in the invasive plant. Bullock Draw Reservoir is a major water source for Pelican Lake. Pelican Lake has been overtaken by EWMF. In order to do a herbicide treatment on Pelican Lake in FY2027, we need to first treat Bullock Draw (and canal that connects to Cottonwood Res, and inlet of Cottonwood Res) for EWMF in FY26 so that it is not reintroduced into Pelican Lake and the system.

Bullock has no fisheries management plan but is part of the predator management stocking plan which consists of Wiper and Tiger muskie as rough fish controls. NER Aquatic Invasive Species biologist has written a draft plan to combat small portions of the EWMF problem.

N/A

Removal/control of EWMF would help with recent fish kills that occur in the hot summer months at Bullock Res. With the success of this project we could work on regaining some of the water storage back via clean excavation in the future.

Chemical removal of EWMF requires a management plan/treatment plan and approval from Ouray Park Irrigation Company.

Acquire funding to purchase the herbicide and administer the EWMF treatment of Bullock Res in July/August 2025. Monitor the effectiveness of the EWMF treatment and do spot treatments if needed.

Yearly monitoring of vegetation density and species, and EWM herbicide spot treatment if needed.

Ouray Park Irrigation Company (watermilfoil causes water delivery issues).

Monitor EWMF treatment and do spot treatments if needed. We would love to be able to better manage Bullock Draw Res as a fishery and make much needed access upgrades in the future.

Removal and control of EWMF are critical to have this as a viable fishery and habitat for waterfowl in the future. We hold the water rights, stock the fish, and invest in the maintenance of the dam.

07/01/2025

06/30/2026

2026

A single lake-wide treatment of ProcellaCOR (EPA Reg. No. 67690-80) at a treatment rate of 2 to 3 prescription dose units per acre-foot was administered at Bullock Draw Reservoir on August 12th, 2025, via boat. ProcellaCOR is a liquid formulation containing florpyrauxifen-benzyl at a concentration of 2.7% by mass. Florpyrauxifen-benzyl is a selective systemic herbicide that is absorbed by Eurasian watermilfoil (EWM) through emergent or floating leaves and from water through submersed plant shoots and leaves. The herbicide is a member of a new class of synthetic auxins, the arylpicolinates, which differ in binding affinity compared to other currently registered synthetic auxins. Treated invasive watermilfoils show a mixture of atypical growth (larger, twisted leaves, stem elongation) and fragility of leaf and shoot tissue. ProcellaCOR targets EWM selectively and, at label use rates, causes little to no damage to native vegetation, fish, or wildlife. Decomposition of treated EWM can reduce dissolved oxygen. Waterbodies with very high plant density are treated in sections to limit the potential for fish suffocation, consistent with the product label. Dissolved oxygen was monitored following the Bullock Draw treatment, and no fish mortality was observed. Irrigation use of treated water follows the agricultural irrigation restrictions on the current ProcellaCOR label (FPL20241025, EPA approved October 21, 2024). Barley, citrus, corn, oats, rice, and wheat require a 24 hour waiting period after application. Soybeans, carrots, canola, sunflower, sugar beets and other vegetable crops, grapes, and tobacco require analytical verification that concentrations are less than 1 ppb. Crops not listed on the label, including grass hay and alfalfa, require verification of crop tolerance before use or analytical verification below 1 ppb. At Bullock Draw, water was approved for irrigation of established grass hay two days after treatment or until testing confirmed less than 1 ppb.

Bullock Draw Reservoir was inspected to evaluate treatment efficacy at the end of September 2025, in November 2025, and again in May and July 2026. No Eurasian watermilfoil was detected. A single strand of Northern watermilfoil was found at the north canal inlet. With the Eurasian watermilfoil removed, native vegetation returned in abundance, including coontail, elodea, and whitewater buttercup. Recovery of the native plant community supports sportfish and native fish species, native macroinvertebrates, and waterfowl.

Yearly vegetation analysis will be conducted on Bullock Reservoir to record native vegetation and macroinvertebrates and determine whether watermilfoil is present. Recovery of native vegetation supports management of the reservoir for DWR fisheries and irrigation use.