FLOOD04954

• County: Costilla
• Community: San Luis
• Basin: Rio Grande
• Title: Subsurface Drainage Feasibilty Study
• Date: 9/1/1996
• Prepared For: Costilla County
• Prepared By: CWCB
• Floodplain - Doc Type: Floodplain Report/Masterplan

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5. Perform engineering analyses which include hydrology, hydraulics, and preliminary
design for the recommended plan.

6. Study alternative solutions to the drainage problem.

7. Prepare preliminary design drawings and construction cost estimates for the
recommended plan.

8. Prepare a reconnaissance-level feasibility report that documents the results of the
study and provides a narrative of the recommended plan.

ill. PREVIOUS ACTIONS AND RELATED STUDIES

The list below summarizes in chronological order the actions and studies, related to
subsurface drainage, that were completed in the Town of San Luis.

1. During the 1930's, the Work Project Administration (WPA) installed a rock lined
subsurface drain parallel to the east side of Highway 159. The drain ran from 4th
Street to Culebra Creek upstream of the old highway bridge.

2. During August of 1987, the CWCB published a Reconnaissance Report which
described the surface and subsurface flooding problems in San Luis. The report
outlined the history of the flooding problems, previous actions taken in the town, and
recommended that a master drainage study be prepared for the town.

3. During December of 1988, WRC Engineering, Inc. published a report entitled
"Master Drainage Study, Town of San Luis, Colorado" for the Town of San Luis,
Department of Local Affairs, and the CWCB. The purpose of the report was to
determine the extent of surface and subsurface drainage problems, to consider
altemative solutions to the drainage problems, and to select a feasible alternative that
could be implemented within San Luis.

4. During 1990 under the direction of the CWCB, subsurface drainage and flood control
improvements were constructed in San Luis. The improvements were recommended
in the Master Drainage Study (WRC, 1988) and included construction of a gravity
subdrain system in the northeast portion of the town. In addition. a levee was
constructed along the east side of town which augmented the existing Corps of
Engineers levee.

5. During November of 1995, the NRCS prepared a letter report which summarized
previous drainage investigations within the town, and summarized a field visit to San
Luis by the NRCS during that same month. The letter report made several
recommendations regarding future drainage improvements. Some of the information
contained within the letter report has been included in this feasibility study.

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