Colorado – Northern Integrated Supply Project (NISP) Phase 1: Alternative Evalutation

The Northern Integrated Supply Project (NISP) is a regional water project intended to provide additional water supplies and management opportunities to constituents within the Northern Colorado Water Conservancy District boundaries. A participant group of 12 water providing entities formed to cooperatively investigate the feasibility of water supply alternatives to meet future water demands.

The main structural component of NISP is expected to be a large off-system reservoir located near the canyon mouth of the Cache la Poudre River. Several smaller project components, such as conjunctive use, storage and river exchanges, and pump-back schemes along the South Platte are being considered. Both the Cache la Poudre and South Platte river basins are tightly administered according to the Prior Appropriation Doctrine. Hundreds of competing agricultural, municipal, and industrial water users rely upon the States’ enforcement of the doctrine to protect their entitlements to river flows. Any new development within the basin would be junior to existing water rights, and could capture only those flows that are unappropriated.

In order to analyze the effects and potential yields for the proposed project components, a river basin network was developed by Riverside Technology, inc (RTi) using the MODSIM water rights planning model. The Cache La Poudre basin is very complex, due to the intricate delivery systems used by the irrigation systems and the multitude of exchanges, augmentations, and trades executed by and between the various water users within the basin. The network model contains over 200 distinct water rights and 31 reservoirs, representing the water portfolios for three municipal systems and twenty irrigation systems. The model simulates both the hydrologic and administrative features within the basin that dictate the allocation and distribution of water.

The water rights planning model will use 50 years of historic hydrologic data (1951-2000) and current basin operations as the baseline scenario. The various project alternatives will be tested individually and in combinations to determine safe yields and evaluate effects upon the river regime.

NISP Participant Boundaries

2290 East Prospect Road, Suite 1, Fort Collins, Colorado 80525  (970) 484–7573  (970) 484–7593 Fax www.riverside.com   info@riverside.com