WSP12086

• File Number: 8449.800.A
• Description: Metro Study SB 96-74
• State: CO
• Basin: South Platte
• Date: 4/1/1998
• Author: CWCB
• Title: Denver Basin and South Platte River Basin Technical Study, Technical Addendum 1 and 2, Senate Bill 96-074
• Water Supply Pro - Doc Type: Publication

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March 21,1998
Page 1-1

Chapter 1: South Platte Basin Inventory

This chapter provides an inventory of the surface water and nontributary
groundwater resources of the South Platte River Basin in Colorado. The purpose of
this inventory is to provide a framework for understanding the "big picture"
interrelationships between South Platte surface water and groundwater resources and
various conservation, reuse, groundwater development and conjunctive use options
being considered by Denver area water providers,

1.1 SURFACE WATER RESOURCES

As part of the surface water resources inventory for the Denver Basin and South
Platte River Basin Technical Study, Hydrosphere and Spronk Water Engineers have
developed flow data for five key gage locations in the South Platte River basin. These
locations include:

. South Platte at South Platte;
. South Platte Below Chatfield;
. South Platte At Denver;
. South Platte at Henderson; and
. South Platte at Kersey.

For most of these locations we have developed preliminary estimates of the following:

. Natural flows;

. Historical flows;

. Future flows;

. Reusable return flow portions of historical and future flows; and

. Undeveloped (free water) portions of historical and future flows,

Based on the availability of data, we have developed these estimates for the 1950
through 1980 period of hydrologic record, This memo describes the information
sources and methodology used in developing these estimates. The results are
presented in tabular and graphical form as attachments to this chapter.

1,1.1.1 Denver Water's PACSM Model

The analyses of surface water resource issues conducted in this study relied in
part on output data from Denver Water's recently developed Platte and Colorado
Simulation Model (PACSM). This study's reliance on PACSM was due to several
factors: