22-090922 - RFP 22-090922 - Design Services for Broomfield Sack Flume

Broomfield’s 2006 Substitution Agreement with the Northern Colorado Water Conservancy District allows the City and County to re-use its Colorado-Big Thompson (C-BT) effluent given it “completely and fully replace(s) such water in time, place and amount as approved by the district.” Reuse of Broomfield’s C-BT effluent will serve as a critical source of supply in the non-potable water system and support the growth and expansion of the City’s reuse system through build out. The agreement states that “until such time that Broomfield can replace all of its C-BT effluent, including effluent returning to Big Dry Creek from outside uses with Broomfield, Broomfield shall install and maintain at its own expense a monitoring system on Big Dry Creek capable of measuring and tracking any C-BT effluent flowing in Big Dry Creek between Broomfield’s wastewater treatment plant and the South Platte River.” 

In 2010 Broomfield entered into an intergovernmental agreement with the City of Northglenn which grants Broomfield the right to use the city’s Sack Permanent Easement to construct, install, and maintain a streamflow gauging station on Big Dry Creek upon the Sack Property (aka the ‘Sack Flume’, see Exhibit 1 for a photo and Exhibit 2 for location of the Sack Flume). In November of 2020, during a routine hydrological calibration of the Sack Flume, it was determined by a State hydrographer that the flume operates at high levels of submergence (or produces inaccurate flow measurements) at all flow rates. Broomfield is responsible for the submergence issue in order for the flume, and the measurements it produces, to be in compliance with the State’s requirements and fulfill its obligations set forth in the 2006 Substitution Agreement.