The Diamond Mountain Lakes (Matt Warner, Calder and Crouse) and the Pot Creek watershed are an incredibly valuable resource for Uintah Basin residents. All three of these lakes are very productive and grow large trout. Fishery management strategies for these 3 lakes include opportunity for family-oriented fishing (put-grow-take) and catch and release trophy. In order for those strategies to succeed, we must be able to overwinter fish in multiple waterbodies. The Diamond Mountain Lakes are among the highest angler use per surface acre in the state of Utah when functioning at their potential. The lakes also provide valuable water storage for residents that live along Pot Creek. The watershed is small and Pot Creek is an ephemeral stream that only flows in the spring and early summer during snow melt. Therefore, water for the reservoirs is entirely dependent on adequate annual snowpack in the headwaters. Low water years contribute to oxygen depletion that has resulted in numerous winter fish kills since 2013. We are able to mitigate winter fish kill conditions through water management and triage, but using a device to increase oxygen availability in these lakes helps us stretch this opportunity much further and eliminates some of the risk of winterkill conditions during shorter-term drought cycles. We completed a SolarBee project on Calder Reservoir September 2022. We have studied the effect the device has had on water quality/dissolved oxygen through several winters while learning some of the issues these devices have. The device has proven effective at mitigating some of the low dissolved oxygen effects we have observed when it is operational. The 2022 Calder proposal was funded by Utah Division of Water Quality as a partnership opportunity. This proposal seeks to match that experience and partnership through DWR to obtain a similar product at Matt Warner Reservoir. The overall goal of this project and others in this watershed is to maintain viable fisheries that do not winterkill.

Purchase a SolarBee water circulator for Matt Warner Reservoir to improve dissolved oxygen during winter months and reduce winter fish kills at the Diamond Mountain lakes, allowing us to balance water management, water triage, and maintaining several fishery management strategies on Diamond Mountain that satisfy the most anglers and angler groups possible.

A SolarBee unit in Calder Reservoir has shown great promise for improving dissolved oxygen during winter months (see attached image). This promise and realized effect has convinced us that pursuing a SolarBee at Matt Warner should improve conditions and fish survival there. This is especially true looking into FY26 because we have been able to overwinter fish for two years in a row at both Calder and Matt Warner Reservoirs, and we hope to be able to continue this trend while we have a healthy fishery. Inaction will lead us to an increased risk to winterkill conditions and/or affect our water management strategies between the lakes. The Diamond Mountain lakes were categorized as Blue Ribbon fisheries for well over a decade before we began experiencing fish declines related to winterkills. When these lakes overwinter fish, the size, growth, and condition of these fish is beyond impressive. If we can utilize technology to limp our fisheries through weak water years, these lakes have the full potential to realize Blue Ribbon status once again.

We are in the process of drafting a Diamond Mountain Fisheries Management Plan. This plan will identify water quality improvement projects as a principle management action we are undertaking to improve fisheries resources, availability, and angler satisfaction for these lakes. As former Blue Ribbon fisheries and hopeful future nominees, this proposal links core values of the Utah Blue Ribbon fisheries plan. Specifically, standards and economic impacts are met when these fisheries are performing at their finest. These lakes exceed the standards category in terms of fish abundance and availability, high-quality outdoors experiences, scenery and aesthetics. The lakes also provide economic value to rural communities, with Vernal being a primary recipient. The vast majority of Calder Reservoir anglers hail from communities hundreds of miles away from Uinta County, with direct benefits for lodging, food, and fuel to Vernal and Dutch John. The core investment value for this management plan is also accomplished where the Blue Ribbon program invests in world-class fisheries to restore habitat, restore fisheries, and gain increased angler access to these resources. This proposal is related to the Utah Division of Wildlife Resources strategic plan with meeting constituency and resource goals. By increasing the capability for these reservoirs to sustain healthy, productive fisheries, we are meeting objective C1 to "increase opportunities for and participation in fishing, hunting, and other wildlife-related activities." By advancing a prescription to maintain lakes with different fisheries management strategies of trophy catch and release and put-grow-take, we are C4 "taking reasonable steps to address our constituents needs, wishes and priorities." Within the resource goals, we are satisfying R1 and R2 by increasing and maintaining these fishery populations and maintaining/increasing the quality of fisheries habitat available.

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We are proposing the purchase of a Solarbee water circulation system. It is a premanufactured device used in lakes all over the country to improve multiple water quality issues. This system will help reduce harmful algae blooms and improve dissolved oxygen. It works by circulating the upper part (epilimnion) of the water column. It is solar powered and can be positioned in the middle of a lake/reservoir. We can expect to see improvements in DO levels fairly quickly upon installation and throughout the winter months. Water quantity could be affected as a secondary reaction. We currently have to play a game of triage and balance to satisfy downstream water user demand for water while holding enough to hopefully overwinter our fisheries. Having some increased trust in our ability to overwinter fisheries may allow us to keep water in places where we may otherwise elect to send water to lower lakes in the system. Every time we deliver water, we incur a substantial "water cost" to the process where we lose a substantial amount of water to "wet" a channel.

No 404 permitting, CWA, archaeological, or NEPA compliance will be required for this project.

UDWR personnel will work with IXOM Watercare to purchase, deliver, and install a SolarBee unit for Matt Warner Reservoir. UDWR personnel will conduct maintenance and monitoring of the unit, as well as monitor changes in water quality. Some funding is listed in the finance page of this proposal to monitor immediate effects.

MiniDOT dissolved oxygen loggers were deployed at all 3 Diamond Mountain Lakes in 2022, and record temperature and dissolved oxygen data every hour. Loggers were suspended 1 meter and 4 meters below the surface. A significant improvement was observed at Calder post-Solarbee vs pre-SolarBee, and the DO logger data will be used to monitor effectiveness at Matt Warner. We continue to deploy these loggers to present day to monitor the effectiveness of the SolarBee structures while tabulating data for the lakes that do not have a SolarBee.

Utah Division of Water Quality has funded the previous structure at Calder Reservoir. We have a similar proposal as this one to DWQ for procuring a solarbee at Matt Warner.

Continue to monitor the effectiveness of SolarBee devices at the Diamond Mountain Lakes. Pending continued success, we may elect to place a second device at Matt Warner reservoir (surface area is larger than the other Diamond Mountain Lakes), and examine the potential to place another at Crouse Reservoir. In the immediate next 5 years these devices are expected to be our main tool to combat low dissolved oxygen conditions associated with winterkill and low water. Our expectation is that these devices will allow us to exceed the Blue Ribbon ranking criteria for these lakes and regain that status.

Maintaining healthy, viable fisheries is vital toward sustainable resource use around Matt Warner Reservoir. This proposal will allow us to advance our goal of maintaining living, viable fisheries, into a 21st century where water is becoming scarce. The lake is an extremely popular camping and fishing destination for anglers from all around and outside the state and has significant external economic impacts. Matt Warner's use includes significant fish harvest. A proportion of Matt Warner reservoir is privately owned and is used for livestock grazing. This project will help minimize the HABs (harmful algae blooms) that occur at Matt Warner, which are detrimental to livestock that use Matt Warner reservoir as a drinking water source.