C153659 Final Report

• Contract/PO #: C153659
• Contractor Name: Metropolitan Water Supply Investigation
• Contract Type: Loan
• Loan Projects - Doc Type: Report

Metropolitan Water Supply Investigation MWSI Process
• scenarios that do not involve borrowing and/or recharge;
• use of alternative sources of surface water supply;
• sensitivity of yields to various levels of demand in the Denver Water service
area; and
• sensitivity of yields to peaking storage availability.
Based upon the modeling results, the alternative sources of surface water supply, and
resulting return flows,potential environment impacts and permitting issues were
generally identified. It was anticipated that early awareness of environmental concerns
would be useful for purposes of formulating specific conjunctive use proposals and for
identifying interested parties and potential approaches to mitigation.
In the Phase III POS, it was also anticipated that the consulting team would provide
technical support for a conjunctive use demonstration project to test the concepts of
recharge, borrowing and payback and to provide assistance in the establishment of
operating rules and accounting requirements. However,there was no activity under this
task, and it was concluded that it would not be feasible to implement such a
demonstration project within the time frame for completion of the MWSI.
Phase III investigations of effluent management included refinements to the Phase II
inventory of reusable supplies , development of a reusable return flow model and
database, estimation of future levels of reusable return flows, and collaboration with
Denver Water to refine estimates of future exchange potential. These efforts involved
analyses of water rights and reusable supplies owned by several water providers that were
not included in PACSM. Phase III work in this area also addressed the potential for
pooling of reusable effluent and altering the timing of use of reusable sources in order to
increase the reliability of reusable return flows for substitution and reuse purposes.
In the area of interruptible supply, the Phase II report provided an overview of concepts,
alternative approaches, and a regional quantification of agricultural supplies that could
conceptually be made available for such arrangements. The Northern Colorado Water
Conservancy District expressed concerns that the Phase II draft report"overemphasizes
the potential for water transfers from the Northern Front Range to the Denver
Metropolitan area." While the intent of the interruptible supply concept was to protect
and continue existing water uses by allowing only temporary transfers,Northern
municipal water providers were concerned about the need to reserve adequate water
supply for growth within their area and the potential economic, social, and environmental
impacts. In response to these concerns, the Phase III POS included further study of
perceived barriers to interruptible supply. This was to address perceptions and
underlying causes of barriers and approaches to overcoming such barriers. However, as
Phase III proceeded, the PMT felt that additional analysis of these issues should be
postponed pending regional planning efforts to be undertaken by Northern municipal
water providers. A Northern Regional Water Coalition has subsequently been formed to
undertake these efforts. Ultimately,the MWSI did not study interruptible supply
arrangements beyond Phase II. In the area of interruptible supply, this report therefore
includes only an updated version of the Phase II report.
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Prepared for the Colorado Water Conservation Board,Colorado Department of Natural Resources by
Hydrosphere Resource Consultants,1002 Walnut Street,Suite 200,Boulder,CO 80302