Weatherby Lake Dam Improvements

Client: Weatherby Lake Improvement Company

Since January 1988, Affinis engineers have been providing professional engineering services to the Weatherby Lake Improvement Company (WLIC) on various projects related to the Weatherby Lake lake, dam, and spillway.  These projects have included:

Design of a new concrete spillway and roadway bridge:  The new spillway is a concrete-lined channel with 110-foot crest tapering to 25 feet. A St. Anthony Falls-type stilling basin was used to minimize cost. The project included a new 25-foot-wide, 110-foot-long roadway bridge to eliminate the roadway crossing through the dam spillway. Work on the $700,000-spillway was completed in 1989.

Design of several lake walls:  In 1992, the final phase of our lake wall project was finished, completing a total of 1,600 feet of shoreline protection.  Our engineers began working with the company in 1991 evaluating wall options. They settled on a modular block system that employs Keystone blocks and Tensar geo-grid, creating an attractive wall that is easily constructed and quickly installed.

Dam abutment grouting:  In 2002, Affinis engineers were asked to evaluate seepage permeating from the lake through dam’s east abutment. Using seepage collected since 1995, it was obvious seepage flow rates had increased dramatically.  Measurements taken in 2002 indicated that about 900,000 gallons were lost each day through the east abutment. We prepared a water budget study for the seepage and ultimately prepared a plan for constructing a grout curtain through the east abutment. We also provided engineering during construction and observation services during installation of the grout curtain.

Lake cross sections and sediment computations:  As part of the lake’s dredging program, Affinis surveyors have taken cross sections at critical coves.  These cross sections are used to determine the amount of sediment filling the lake.  We complete these cross sections at some locations annually and at others bi-annually.

Peret property water quality facility:  In 2005, WLIC asked Affinis to provide engineering services for a water quality facility upstream of the main lake.  Our engineers developed schematic plans for a 40-acre property WLIC had purchased for the purpose of reducing sediment transportation and attenuating peak flows into the north cove of Weatherby Lake.  Our services included evaluating several alternatives including do-nothing, a wetland-only option, a series of ponds option, and a dam and lake option.  Based on our analysis, WLIC selected to proceed with the dam and lake option for the 40-acre site.

COMPLETION DATE: ON CALL SERVICES PROVIDED

COST: N/A

PROJECT PHOTOS (Click to enlarge)