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~ " .Ii .'.i. " e: . A perforated subdrain in the central part of town would help to alleviate the groundwater problems, and a gravity system would be the most desirable because of cost, I maintenance, and operation issues. The new subdrain would likely be independent of the original subdrain, and would terminate no further south than 4th Street. The CWCB roughly bstimates that construction of the new subdrain would cost about $150,000. . A practical "daylight" location for the potential gravity subdrain is at the drainage ditch on the south side of town upstream of Culebra Creek. It is imperative that the exikting drainage ditch that runs parallel to the new levee be cleaned and maintained regularly by the county. A gravity subdrain iu the south part of town does not seem to be practical dL to existing artesian wells (6 or 7), existing wetlands, and inadequate ground slopes. Sh~llow roadside ditches in the south part of town could help direct surface water towards Culebr~ Creek. A groundwater infiltration test may not be necessary due to the previous work lat was done within San Luis. Information from the 1988 report would be useful for helpi~g to design a subsurface drain in the central part of town. . . . The roadway modifications and closure structures at 4th Street, 6th Street, and Gaspar Street that were supposed to be part of the 1992 levee construction were never completed by the county as part of their cost share program. It is likely that this work would hJve to be done I before any additional state funding was made available for future projects. ~he road work near the levees could be coordinated with other county road repair projects to sTe money. The RC&D (contact Jim Mietz) may be a funding source for future projects. Tile NRCS does not have resources or funding for project implementation. I . Recommendations and Actions I The CWCB and the NRCS should independently develop a conceptual project design to address groundwater problems in the central portion of the town of San Luis. Additional mbetings in San Luis will be held on a later date (tentatively 11/21/95) to discuss the potential project. A small technical meeting will be held in the afternoon, and a large public meeting will be held in the evemng. Prior to the next meeting, the CWCB should prepare a feasibility study (conceptual level only) which will address mitigation activities for groundwater problems. The activities t6 be addressed in the study would include the following items: . Determine the alignment and approximate depths of a subdrain system that jOUld help 1to mitigate groundwater problems. Size the perforated and non-perforated subdrain pipes using information and estimated groundwater hydrology characteristics from the previous study. . 2