PUB00094

• Year: 1998
• Title: Denver Basin and South Platte River Basin Technical Study: Technical Addendum 1 and 2
• Author: Special Water Committee
• Description: Technical addendums for the report
• Publications - Doc Type: Tech Report

I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I
I

Chapter 1: South Platte Basin Inventory

March 21,1998
Page 1-3

water to a diversion or reservoir based on available flow (including both natural flows
and allocable return flows), water rights, diversion or storage capacity, and demand,

In developing PACSM, Denver has provided the most detail for those portions of
the South Platte and Colorado basins which have the most direct effect on Denver's
raw water system. For example, PACSM contains a very detailed representation of
natural flows, water rights, transmountain imports, reservoirs and project operations for
the South Platte above Strontia Springs because Denver has extensive water rights
and facilities in this sub-basin. In comparison, PACSM currently represents the Plum
Creek, Cherry Creek and Clear Creek basins simply as historical inflows to the South
Platte based on gage data. It should be noted that Denver Water is continually refining
its PACSM model. Generally speaking, PACSM currently represents the following
aspects of the South Platte Basin in a highly detailed manner:

. Natural flow hydrology, water rights, transmountain imports and project
operations in the South Platte and its tributaries above Strontia Springs
including Denver's and Aurora's raw water systems and Thornton's South
Park water rights.

. Hydrology, return flows, water rights and project operations for the South
Platte main stem between Strontia Springs and the Henderson gage
including Centennial's. and Englewood's surface water systems, PSCO's
Arapahoe, Zuni and Cherokee power plants, and the Burlington System.

. Metro, Bi-Cities and Marcy Gulch wastewater treatment plant flows consistent
with modeled water demands levels,

. Stream gains due to stormwater runoff from urban areas,

. Hydrology and water rights on Bear Creek below the Morrison gage.

. Denver's and Aurora's exchange rights between Metro and Strontia Springs,
Cheesman and Spinney Mountain reservoirs,

. South Platte water rights calls from below the Henderson gage. These are
modeled based on the historical relationship between Henderson flows and
downstream calls.

The following aspects of the South Platte Basin are currently represented in
PACSM in a relatively less detailed manner or are not explicitly included in the model:

. Cherry Creek and Plum Creek inflows to the South Platte are simply
represented as the historical gage flows for Cherry Creek below Cherry Creek
Reservoir and Plum Creek at Titan/Louviers, respectively, As such, they do
not reflect changes in flows that may occur due to urban stormwater runoff,
municipal wastewater discharges, augmentation and reuse activities. storage
projects, or changes in discharges to surface drainages from increased
pumping of the Denver Basin aquifers.

. Clear Creek inflows to the South Platte are simply represented as the
historical gage flows for Clear Creek at its mouth.

Hydrosphere Resource Consultants, 1002 Walnut Suite 200. Boulder, CO 80302