PUB00102

• Year: 1998
• Title: Denver Basin and South Platte River Basin Technical Study
• CWCB Section: Water Conservation & Drought Planning
• Author: Simpson/Lile
• Description: Results of study to investigate Denver Basin groundwater management and South Platte River Basin issues
• Publications - Doc Type: Brochure

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. The SB74 Study's
computer-based interactive tool is helpful in understanding the numerical
information presented in this chapter.

Key points:
1. Undeveloped flows or developable flows are significant in above average
runoff years. Most of the developable flows occur below the metro Denver
area. (Figs 1-17 to 1-19 Chapter 1, Technical Addendum No.1)

2. Additional reservoir storage or ASR (Aquifer Storage and Recovery) would
allow the use of these developable flows.
3. Platte River Three State Cooperative Agreement would need to be
implemented in order to meet: Endangered Species Act requirements
associated with future use of the developable flows.

ChaDter 3 - Estimate of the Impact on Runoff to the South Platte River from
Construction of Impervious Surfaces in the Denver Metropolitan Area for the
Period 1950-1995 (Technical Addendum No.1, Chapter 4)

This chapter describes an analysis of the increase in South Platte River gains
through the Denver metropolitan area over the past several decades as a result
of urbanization. The approach used to estimate the increased stream flow gains
assumes the gains have resulted primarily from (1) runoff from impervious
surfaces (RIS), and (2) lawn irrigation return flows (URF).

Key points:
1. Based on preliminary research, the non-reusable increase in runoff from
impervious surfaces was approximately 52,000 acre-feet and the non-
reusable lawn irrigation return flows was approximately 21,000 acre-feet,
or a total of approximately72,000 acre-feet.
2. The total streamflow gain from urbanization is approximately 0.10 cfs per
1,000 persons, or 72 acre-feeVyear
3. Some Peer Review Group members suggest this increase in runoff should
be considered as an offset to Denver Basin aquifer pumping impacts.
4. Additional studies are needed to more accurately quantify the amount and
timing of increases in runoff from impervious surfaces.

C"aDter 4 -Inventory of Existing Water Efficiency Practices (Technical Addendum No.
1, Chapter 2)

Hydrosphere conducted a survey of the water conservation practices of the City

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