PROJ00518

• Contract/PO #: C153484
• Contractor Name: San Luis Valley Water Conservation District
• Contract Type: Grant
• Water District: 0
• County: Rio Grande
• Bill Number: FSG
• Loan Projects - Doc Type: Feasibility Study

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same year and perhaps used more efficiently by existing diversion

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structures.

River Basin Modeling

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The 1948 through 1985 period was selected as the historic hydrologic period for

use in the river basin modeling. This period was selected based on statistical

analyses and other factors including data availability, public perception, and

inclusion of drought periods.

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The computer model used for the storable flow analyses was the RIver Basin

SImulation Model (RIBS 1M) which allocates flow on a monthly basis by the prior

appropriation doctrine.

Modifications were made to the model to incorporate

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features such as administration of Rio Grande water rights, the Rio Grande
Compact and the Closed Basin Project.

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The primary data generated for the modeling effort consisted of:

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a flow base containing monthly flows at various locations along the

river on which to superimpose the modeled features of the basin.

The flow base was generated by adjusting 1948 through 1985 gaged

flows in the basin to remove the effects of man made structures

included in the modeling.

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2.

a water user network which contains information on how the model

is to operate the modeled features.

This network contains such

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information as the location, priority, constraints, and return flow

characteristics for each diversion. Additional information such as

starting contents. area-capacity curves and evaporation rates are
included for each modeled reservoir.

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A process (called calibration) of checking and adjusting the model to reasonably

match a historical record of diversions and streamflow yielded a model suitable

for the storable flow determinations. The 1950 through 1967 period was chosen

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