SPDSS_Task42-2_Phase2_DenverBasinAquiferConfiguration

• Title: SPDSS Task 42.2 - Denver Basin Region Aquifer Configuratioin - Phase 2
• Description: This Technical Memorandum was undertaken under Task 42.2, and summarizes the compilation, analysis and mapping of existing published aquifer configuration data for the Denver Basin Region.
• Decision Support - Doc Type: Task Memorandum
• Date: 2/13/2006
• DSS Category: Groundwater
• DSS: South Platte
• Basin: South Platte
• Contract/PO #: C153953
• Grant Type: Non-Reimbursable
• Bill Number: SB01-157, HB02-1152, SB03-110, HB04-1221, SB05-084, HB06-1313, SB07-122
• Prepared By: CDM

SPDSS Phase 2 Task 42.2 Denver Basin Region
Aquifer Configuration Technical Memorandum
FINAL
To: Ray Alvarado, CWCB
From: Camp Dresser and McKee Inc.
Donavon Paschall, Gordon McCurry, and Matt Bliss
Subject: SPDSS Groundwater Component Phase 2, Draft Final Task 42.2
Denver Basin Region Aquifer Configuration Technical Memorandum
Date: February 13, 2006
Introduction
The groundwater component of Phase 2 of the South Platte Decision Support System
(SPDSS) focuses on compiling and evaluating available relevant data to support the
Decision Support System (DSS) for the South Platte River watershed and to add the data
to HydroBase, the State of Colorado's hydrological database. The SPDSS study area is
presented in Figure 1. For the purposes of the SPDSS, the groundwater study area is
divided into two hydrologic regions. The Denver Basin Region includes the bedrock
aquifers of the Denver Basin. The South Platte Alluvium Region consists of the
unconsolidated deposits of the South Platte River mainstem, extending downstream
from just below Chatfield Reservoir to the Nebraska state line at Julesburg. The South
Platte Alluvium Region also includes the alluvium overlying the Denver Basin Bedrock
Aquifers in Water Divisions 1 and 2.
The current definition of the Denver Basin Aquifers was established in 1985 with
promulgation of the Denver Basin Rules, 2 CCR 402-6 (Division of Water Resources
[DWR] 1985). The four principal bedrock aquifers of the Denver Basin are, from top to
bottom, the Dawson, Denver, Arapahoe, and Laramie-Fox Hills Aquifers. The Dawson
and Arapahoe Aquifers have been subdivided by the Colorado Division of Water
Resources (DWR) into Upper and Lower units based on the presence of lower
permeability claystone and shale layers in their respective northern extents (Figure 2).
This task was undertaken for the Colorado Water Conservation Board (CWCB) and the
DWR, under Tasks 31 and 42 of Phases 1 and 2 of the SPDSS by Camp Dresser & McKee
(CDM). Tasks 31 was undertaken in Phase 1 and included the collection of existing
published aquifer configuration data. Task 42 was undertaken in Phases 1 and 2 and
included the collection of additional published data and the analysis and mapping of
these aquifer configuration data. The objectives of these tasks are as follows:
1. Compile existing aquifer configuration information and create a HydroBase-
compatible database with data from the Denver Basin and South Platte Alluvium
regions to enhance the understanding of the system.
2. Help identify additional data needs in these regions.
3. Support the design of the groundwater field program.