Rinn Valley Reservoir Complex is located at  10504 Co Rd 7, Longmont, CO 80504.

The Rinn Valley Reservoir Complex was funded by the Groundwater Management Subdistrict (GMS) Bond approved in 2012. This project will add an additional 2800 acre feet of water storage to the GMS augmentation plan.  

Components of the project include two inlet structures to Phase 2 Reservoir to efficiently measure variations of inflows from 1 to 60 cubic feet per second (CFS).  A 24” Parshall Flume will measure flows from 1 to 10 CFS and a broad crested weir will measure flows from 10 to 60 CFS.  A rip-rap run down channel in the reservoir bank will safely move the water from the measurement structures to the reservoir.  Additionally, a discharge from the Phase 2 Reservoir Pumpstation will be constructed in the bank of the Rural Ditch, and the water will be conveyed to the St. Vrain River by carriage in the Rural Ditch. A pumpstation located in the Phase 2 Reservoir will be constructed to discharge up to 12 CFS.  

The pumpstation design is an adaptation of the pumpstation constructed at Shores Reservoir Pond A.  The concept is a sloping column pipe which accommodates a submersible pump that is lowered to the bottom of the reservoir.  The pump delivers water up the column pipe, measured by means of a meter and discharged to the Rural Ditch. The pumpstation will also deliver water to the Phase 1C cell, which is west of the pumpstation.  A 24” PVC pipe discharging from the pumpstation to a rip-rap rundown channel gets the water to Phase 1C.

Source of Water:
South Platte River and its tributaries.

Date of Appropriation:
December 31, 1991.

Amount:
1300 acre feet, conditional, with the right to refill; Lupton Bottom

Ditch diversion, 115 cubic feet per second, 100 cubic feet per second conditional