Dams and Fish Ladder 2

Lake Limerick community is made up of two man made lakes and three Dam structures, providing us with a lovely residential area with abundant recreational opportunities.   All three Dam structures work in conjunction with one another to make this community what it is today.

LIMERICK DAM

Limerick Dam #MA14-130 Limerick Dam is an earthen filled dam impounding Lake Limerick, which is used for various recreational purposes.

The dam embankment is approximately 400 feet long, 28 feet high and the crest is 16 feet wide. The dam has a 28-inch outlet pipe through its approximate center that can, in an emergency, aid in release of water in addition to flows from the spillway. A concrete spillway with fish ladder is located on the east side of the embankment. Limerick dam impounds 920 acre feet of water at the spillway crest.

Lake Limerick receives water from Cranberry Creek, outflow from Lake Leprechaun, 2 small unnamed spring fed streams in the northeast portion of the lake, 1 unnamed stream in the eastern portion of the lake, and natural springs from the lakebed.

LEPRECHAUN DAM

Leprechaun Dam #MA14-113 Leprechaun Dam is an earthen filled dam impounding Lake Leprechaun, which is used for various recreational purposes.

The dam embankment is 162 feet long, 12.5 feet high and the crest is 30 feet wide. The dam crest is paved and used as a residential street/county road. A 42-inch pipe through the crest embankment serves the concrete spillway box outflow and has a 15-inch slide gate for lake discharge during repairs. The reservoir capacity is 86-acre feet at the dam’s crest.

Water is fed to the reservoir by 2 small creeks and natural springs. Water flows from the reservoir to Lake Limerick at a pool elevation of 456 feet.

CRANBERRY CREEK DETENTION STRUCURE

Cranberry Creek Detention Structure #MA14-594 Cranberry Lake is a natural lake and wetland area located ¼ mile west of the Lake Limerick community. The structure was built at the direction of Washington State’s Environmental Protection Agency in the 1980’s. The Cranberry Detention Structure and basin federal identification is #MA14-594. The structure consists of approximately 7,000 cubic yards of fill, 220 feet long and 60 feet wide. The crest is 18 and 10 feet above the streambed. A gravel road runs its full length. The stream elevation is 461.5 feet.

Three 48-inch culverts pass through the center of the structure. The center fish passage culvert starts at elevation 461.5 feet, has a 1.67% slope, and ends at a downstream elevation of 460.5 feet. The other two culverts have inlet elevations of 464.0 feet. As a result, all flows pass through the fish passage culvert until flow rates reach 40cubic feet per second.

Reservoir Level Operations Lake Limerick receives continuous flow from Cranberry Lake to the west, Lake Leprechaun in the northwest, and intermittent stream flows from wetlands to the northeast. Lake Limerick’s reservoir levels are maintained for recreational and fish habitat/passage purposes throughout part of the year via a weir board system. The weir boards are installed to increase the elevation of the lake level during the spring, summer and early fall. This is done in part to help the Cranberry Creek watershed fishery by compensating for water that would be otherwise lost to the watershed due to evaporation and water out-flow from the lake. The extra water made available maintains flow in Cranberry Creek downstream from the dam. The higher water levels also help to ensure provision of irrigation water for the golf course, and enhances recreational swimming, fishing, and boating uses. Specific timing of weir board placement and removal is dependent on water inflow, lake water levels, lake usage, and forecasted weather, but usually begins in April and ends in October.

Lake Level Management / Annual Weir Board Adjustment Schedule The lake’s water level is raised in the spring by placing eighteen weir boards in a frame six (6) boards wide and three (3) boards high for a total height of 12.0 inches (measured lakeside from the crest of the concrete spillway). Providing no severe rain events are predicted, weir board installation starts the first week of April. The boards are placed so as to not raise the water level more than one (1) inch per day. Traditionally, placing 1 weir board per day within the weir board framework supports this requirement, assuming no abnormal precipitation that would naturally make the lake level rise. Weir board installation is normally completed by the fourth week of April in time for fish planting and Washington State’s opening day of fishing season. Lake Limerick’s lake level is monitored on a daily basis via a data logger that digitally measures lake level height. This data set is used to help ensure the lake level height remains near the prescribed lake level height stated above. The lake level is actively managed via weir board adjustments as needed during the recreational season. Should the prescribed lake level height be deemed undesirable by the LLCC Board of Page 6 Lake Limerick Dam O&M Manual – December 02, 2023 Directors, weir boards may be added or removed to obtain the desired level for recreational use, support lake health issues, or address other unforeseen issues that could cause harm to the lake or shoreline. The Lake Limerick’s fish ladder weir boards are managed by LLCC during the recreational season and by the Squaxin Tribe during the salmon migration season. Should the lake level fall to a point where water flow through the fish ladder may be compromised, weir boards within the ladder will be removed to help ensure continuous water flow. Weir boards removed at the end of summer must be removed slowly in order to not decrease lake levels more than one (1) inch per day. Weir boards within the fish ladder are the last to be installed and first to be removed. Weir board removal may start as early as September 15th if lake levels are up and significant rain has begun, or is predicted, to begin soon. If the summer weather has been normal and the weather forecast is for fair weather, weir board removal should start October 1st.. In any case, weir board removal must start early enough to ensure complete removal by October 31st to support salmon migration and reduce shoreline property damage resulting from fall/winter high water levels. Equipment Operations-Lake Limerick Air Operated Butterfly Valve The compressed-air-operated butterfly valve is located at the upstream end of the main outlet

Reservoir Level Operations – Lake Leprechaun receives flow from a wetland area upstream from the lake. Leprechaun Dam is operated for flood control and recreational uses. During flood control conditions, a large white PVC float diverts floating objects and debris that could plug the 7-foot by 8-foot Spillway box. When lake level elevations are between 467.8 and 470.8 feet the grating on the spillway box must be checked every 3 to 4 hours and all debris removed. At lake level, elevation is 470.8 feet, water will begin to flow over the top of the spillway box at which time the 15-inch gate valve handle will be difficult to operate. Annual Weir Board Adjustment Schedule-Lake Leprechaun The lake level is changed in the spring and fall. Beginning the first week of April, six (6) weir boards are placed in a frame, raising the lake level at a rate not to exceed one (1) inch/day, for a total elevation increase of 15.25 inches. All weir boards will normally be installed by the third week of April to support fish planting prior to the Washington State’s opening day of fishing season. Weir board removal begins October 1, lowering the lake at a rate not to exceed one (1) inch/day, and will normally be completed by October 31.