PRRIP: Colorado's Depletions Plan

• File Number: 8461.250
• Description: Water Issues
• State: CO
• Basin: South Platte
• Water Division: 1
• Author: Ted Kowalski
• Title: PRRIP: Colorado's Depletions Plan
• Water Supply Pro - Doc Type: Project Overview

I. SOUTH PLATTE RIVER BASIN
A. Population Estimates.
The 1997 "Population Baseline" for Colorado's Future Depletions Plan is:
l. Northern ReQion -- Boulder, Weld, Larimer, Washington, Morgan, Sedgewick, Logan,
Phillips (701,470)
2. Central Region -- Denver, Jefferson, Adams, Clear Cree'k, Gilpin, Park (1,766,207)
3. Southern Rep-ion -- Arapahoe, Douglas, Elbert (194,602)
Within 90 days after the inception of the Program, the Colorado S1:ate Demographer shall report
the amount by which the population of each region is expected to i.ncrease over the Population
Baseline by the end of the initial reporting period ("projected Population Increase"). At the end
of each reporting period, Colorado will provide the Governance Committee an estimate by the
Colorado State Demographer of the actual population in each region (which shall be the
Population Baseline for the next succeeding reporting period), and an estimate of fhe projected
Population Increase for the next succeeding reporting period.
B. Water Use and Effect Assumptions.
Assumptions concerning per capita water use, supply source mix by region, and
accretive/depletive effects of each supply source (including month.ly distributions of said
effects), set forth in this paragraph and the table below, represent reasonable estimates at the
outset of the program, and may be modified by the Governance Committee based on information
made available to that Committee by Colorado or others. The gr•oss per capita water requirement
in the South Platte River Basin in Colorado will be assumed to be 0.27 af/yr, with 35%
consumptive use assumed for all municipal purposes, and 45% coinsumptive use assumed for
agricultural irrigation purposes. It is anticipated that new water related activities within the three
regions will be from six sources of supply to serve the Population Increase, each with a different
depletive or accretive effect on flows in the South Platte River. Th,e three regions will devalop
the six sources of supply in different combinations. It will be initially assumed that the sources of
supply for new water related activities will be developed in the combinations and will have the
accretive or depletive effect shown below:
Source
New Transbasin Imports
Nontributary Groundwater
Ag. to Urban Conversion
Conservation
Wastewater
Exchange/Reuse
Native South Platte Flows
Northern Central Southern Accretive (or Depletive)
Region Region Region EflFect
40% 30%
0% 10%
35% 5%
5% 15%
10% 25%
10% 15%
20% Fi4(%
50% Ei8%
0% 10`%
10% 00/0
10% (41%)
10% (2i'%)
October 24, 2006 Colarado Depletions Plan