Devils Lake Navigator

DISTRICT MONITORS LAKE LEVEL

During the upcoming December board meeting the DLWID staff will present the Lake Level Report they have been working on the past few month. According to the report “the impoundment regime change for 2012 is being reviewed. Previously the lake was impounded to a height of 9.53’ beginning as earlier as April 15 through October 15th. In 2012 this was modified in an attempt to mitigate impacts that impoundment has on the erosion, the shoreline vegetation, and fish and wildlife. Following two public hearings on this matter, the Devils Lake Water Improvement District Board of Directors opted to begin impoundment no earlier than June 1st, with a target date of June 15th, and then only to 9.0’. This impoundment regime was conducted during the summer of 2012, and this review is meant to provide insight to the District as to the impacts pro or con that may have had. Considerations will include recreational access, fish passage, septic systems, and water quality, shoreline vegetation.”

We have taken the report and posted each section on this website.  Each section has the heading Lake Level Report.  There are five section in all

1. Boat Dock Survey
2. Fish and Wildlife
3. Septic Systems
4. Water Quality
5. Vegetation

We have presented this material without commentary.  We will submit a request to the DLWID board to have this material presented an more than one meeting as December 13 is in the midst of the holiday season and it is unlikely anyone will be in attendance at the meeting.  In the meantime we suggest you review all five sections and draw your own conclusions.

RECREATIONAL ACCESS — BOAT DOCK SURVEY

A section from the Lake Level Monitoring report contained in Staff Report from the December 13, 2012 board meeting material.  This section drafted by district staff.

The Devils Lake Water Improvement District conducted a boat dock survey this fall. Water depths were taken at each of the 393 structures on Oregon Department of State Lands list of registered and unregistered docks for Devils Lake. These predominately were located in the jurisdictional waters of the state, although some docks which were measured were outside this boundary in dredged out areas or canals. Depths were recorded at 1 to 2 spots on the dock. The primary depth was taken at the point where the motor of a boat would typically be located if moored at the apparent preferred docking locale. For some docks an optional mooring site was recorded which may provide the upland land owner another position within the existing configuration of the dock to moor their boat. The Crystal Lagoon area was not surveyed, but previous outings confirm this area is utilized and anecdotally favored by non-motorized crafts such as kayaks and canoes. Non jurisdictional docks exist in the back canal system, nor for the most part exist as the width of the canal system largely precludes such structures.

Depth soundings were taken using a fixed device with a 6” square base to standardize the measurements in the variable substrates (muck, sand, bedrock). Depth measurements were recorded in 3” increments which were later converted to decimal feet. Given the nature of taking depths from a boat in real world conditions, the surveyors were conservative in their recording, erring on the low side of a measurement. In other words, the measurements were made in a way that may have slightly underestimated the actual depth of water available by up to 3”. The current lake stage was recorded for each day of sampling, and the depths normalize to water depths of 9.53’ (maximum impoundment), 9.0’ (2012 impoundment), and 8.6’ (anticipated water height after evaporation period for 2012 – this is also near the typical water height seen in the late summer predam modification in 2006). Continue reading →

FISH AND WILDLIFE

A section from the Lake Level Monitoring report contained in Staff Report from the December 13, 2012 board meeting material.  This section drafted by district staff.

Devils Lake is home to a genetically distinct line of federally listed Coho Salmon. These fish make their upward migration in the winter period, when the lake is not impounded, but their outward migration occurs from May to Mid July which is typically a period of impoundment. In 2012 the impoundment period was reduced to beginning no earlier than June 1st, with an anticipated impoundment starting date of June 15th, based on lake level at the time. Historically the lake was impounded from April 15th. The District had a practice of pulsing the dam every other night from May 15 to May 31 in an attempt to mitigate some of impacts to juvenile fish trying to make their way to sea. Non-native ambush predators such as large mouth bass and other piscivorous fish may take advantage of the shadowy, narrow outlet the juvenile Coho would necessarily have to traverse in their escapement. Continue reading →