Judy Reservoir in winter

Cultus Mountain Watershed

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The Judy Reservoir system obtains its water from four streams in the Cultus Mountain watershed (Gilligan Creek, Salmon Creek, Turner Creek, and Mundt Creek). A diversion pump station provides raw water from the Skagit River. The Cultus Mountain watershed starts about two miles due east of Clear Lake — all the streams in the watershed drain eventually to the Skagit River.

Water Source

Water is collected from the four Cultus Mountain streams at diversion structures and transported to an impoundment (Judy Reservoir) through two collector pipelines. The diversion structures are set up on a bypass system, allowing water to flow past the diversion. Instream flows set by rule under WAC 173-503 limits the diversion quantities available from each stream based on the month of the year. When the water measured on a downstream gauge does not meet these minimum flows, Skagit PUD will divert water from its supplemental point of diversion on the Skagit River up to the maximum water right for each stream, as necessary.



Judy Reservoir lies in a natural basin through which Janicki Creek once flowed. In 1946, Janicki Creek was diverted around the basin's eastern edge, and dams were constructed with a spill elevation of 437’ above mean sea level (AMSL) and a capacity of 450 million gallons. The dams are “A” Dam to the southwest and “B” Dam to the northeast. “B” Dam is actually two dams on either side of a rocky knoll. Dams “A” and “B” were raised in 1965 to increase the Reservoir spill elevation to 451’ AMSL and the capacity to 1,010 million gallons. The dams were raised again in 1999 to increase the reservoir spill elevation to 465’ AMSL and the capacity to 1,450 million gallons. Janicki Creek continues to flow in a new channel along the east side of the reservoir. It meets Judy Reservoir’s spillway at the northeast corner of the reservoir.

The spillway empties below the dam into the existing bed of Janicki Creek, a tributary to the Skagit River. In the past, the stream water filling Judy Reservoir was adequate to spill the reservoir for about five months each year, from February through June, which flushed undesirable organics from the reservoir that may have accumulated during the other seven months. The system demands exceeded inflow from the streams around the end of June, causing the reservoir pool level to drop below spill. This trend continued for about 120 days through the peak demand and low rainfall season until around the end of October, when stream inflows exceeded demands, and the pool elevation rose.

The reservoir typically reached spill elevation by the end of January, and the cycle began again. With the increase in Judy Reservoir's capacity and a combination of stream flows and river pumping to replenish drawdown, the reservoir has greater potential to stay full during the year and provide more readily available capacity for emergencies.

The PUD has water rights to all four streams, the Skagit River, two groundwater wells, and the Judy Reservoir storage.

The PUD also obtains water for the Judy Reservoir system from the city of Anacortes through interties. These interties are connected to the city’s transmission line system, which starts from its water treatment plant adjacent to the Skagit River in Mount Vernon and extends westward to Anacortes on Fidalgo Island. Water is purchased from the city of Anacortes under the terms of a water contract. The city obtains water from the Skagit River through its certificated water rights.