Union Reservoir, Longmont Colorado - Union Lake, just east of Longmont, is proving to be one of the states premier wiper lakes offering good fishing for bass and walleye as well.
Originally called Calkins Lake, the Union Reservoir was carved out during the last glacial age and is one of only a few natural lakes in Colorado. In 1903, the Union Ditch Company began drilling a tunnel to release water into the St Vrain River. According to Colorado water law, that made Union a true reservoir. Today, visitors to Union Reservoir enjoy fishing, swimming, wakeless boating, camping, windsurfing and picnicking. The Reservoir is located approximately 7 miles west of I-25. Union Reservoir offers camping beginning May 1st. No hookups or dump stations are available. The trailer sites are located near the waterfront and offer a picturesque view. The tent sites are located near the beach.
2010 CDOW Fishing Forecast from CDOW http://wildlife.state.co.us/NR/rdonlyres/204390F2-B098-47BD-89A1-D6659AC378D3/0/UnionReservoir.pdf
Wiper –Fishing for wiper during 2010 should be quite good. Deploying 5 gill nets, a total of 78 wipers were collected during the fall 2009 survey. Legal size fish (>15”) were plentiful. Of the 78 wiper sampled 54% (42 fish) were greater than 15” in length. This proportion increased from 42% based on the 2008 survey. This fishery survey only measured a small fraction of the total wiper population so be assured there are hundreds if not thousands of 15” wiper in Union! Union is managed primarily for wiper with walleye being a far second. In general I am looking for roughly 20 fish per net of the principle predator (wiper in this case). My management fell short of this goal (15.6 wiper per net) in 2009 so look for a slight increase in the number of wiper stocked in 2010. Keep in mind simply stocking more fish is not always the best means to an end. As the number of predatory fish increases in any particular water, so does competition for food, resulting in much slower growth rates.
Walleye –The 2009 gillnet survey indicates walleye fishing at Union should be fair this year. Union reservoir is primarily managed for wiper. Accordingly the gillnet survey exhibits these results. Anglers seeking better walleye numbers might consider other options (see additional DOW summaries). On average, walleye measured 11” and weighed about 1 lb. In total 22 walleye were collected, with 32% (7 of 22) exceeding 15”. A solid year class of walleye stocked in June 2009 will reach 15” during the fall of 2011. There is a gap in year-classes (11-13” fish) as no walleye were stocked in Union during 2008.
Gizzard Shad – Serving as the primary food source for all adult game fish, gizzard shad are the most important prey species in Union Reservoir. Overall abundance of adult shad remains at sufficient levels to grow sport fish such as walleye, wiper, and catfish. Casting or trolling a shad imitation at Union is a good bet!
Catfish –Zero channel catfish were collected during the 2009 gillnet survey but anglers routinely catch large cats at Union. Given the sedentary nature of catfish, the sampling gear used limits our ability of gage the structure of the catfish population. Since 2006 the DOW has stocked more than 86,000 catfish fingerlings (2-3”) so catfish anglers should make their own evaluation at Union.
Future Management–Based on the traditional success of wiper and the somewhat lackluster performance of walleye at Union, significantly more wiper than walleye will continue to be stocked in Union in the future. Catchable (10”) rainbow trout will be stocked during the spring and fall to provide an additional angling opportunity. Black crappie will also be stocked however the success of this species is limited by poor habitat and wiper/walleye predation.
Getting there: Take I-25 to Highway 119 (Longmont exit). Go west to County Line Road 1. Go north approximately 3/4 of a mile and turn right at the sign for Union Reservoir. The entrance is about 1/2 mile up this road on your left. Fees: Daily: Vehicle - $8 Trailered Boat - $8 Annual - $65.00 Annual Boat - $40.00 Citizens of Longmont pay $55/vehicle, $40/boat for annual pass Bicycle / Walk-in (per person) $2 Boating: Wakeless. Wakeless only, observe all typical Colorado boating regulations
Union Trailer Sites# of Sites: 28 Fees: $8 plus gate fee
Open May 1. There are good trailer sites in the wide open area to the north of the boat ramp. There are no hookups or dump stations. Very close to inlet for good fishing. Sites are very close to one another.
Union Tent Sites# of Sites: 14 Fees: $8 plus gate fee
Open May 1. These sites are fairly wide open, but offer a nice place to stay if you're looking to do other things than be out in the wilderness in total seclusion. The sites are available for reservation by phone at 303-772-1265.
