This alternative would involve creating new runoff conveyances in up to 10 locations at the ranch. The relocation of drainage swales would involve connecting existing swales to new depressions (0.5-1.0 foot depth over a broad area) in order to redirect stormwater runoff away from new and historic structures. All of the relocated swales would reconnect with natural drainage conveyances prior to leaving the 40-acre parcel. Within the 40-acre parcel boundary, these new conveyance depressions would result in minor changes to hydrologic patterns. (Outside of the 40-acre parcel boundary, there would be no effect to the natural hydrologic patterns.)

The addition of impervious surfaces at the ranch would have a minor effect on runoff volumes (increased) downstream of the 40-acre parcel. The predominant soil type at the ranch has relatively low natural percolation rates and naturally provides moderately high volumes of runoff.

The newly restored areas included in the Proposed Action would ultimately intercept rainfall and runoff better than bare, disturbed ground. Restored areas would therefore help to offset increased runoff effects resulting from additional impervious surfaces associated with new buildings and other site uses.

Additionally, in the long term, ongoing regular maintenance of drainage swales (e.g., grading, cleaning out culverts, etc.) would help to prevent damage from large precipitation and runoff events.

The effects to groundwater, including water quality, as a result of the increased water demand would be negligible. A 2008 Water and Power Demand Study estimated normal daily water demand would be less than 3,000 gpd for the Proposed Action. During periods of higher visitation, these demands would likely range from 15,000-20,000 gpd. As described in the Chapter 3, Affected Environment, existing water rights allow for an average of 12,275 gpd. Even with occasionally existing water rights. In the long term, as long as increased water demands remain below the existing water rights threshold, no measurable adverse effects to ground water are anticipated.

Ultimately, the Proposed Action would not result in any long-term adverse changes to hydrologic or soil patterns on the ranch.

The majority of lands upstream of the 40-acre parcel is largely undeveloped and has, in most cases, successfully re-established native vegetation following the removal of cattle grazing in the Piute-Eldorado Valley. As such, past actions have minimal influence on hydrology at the ranch and areas downstream of the 40-acre parcel. No reasonably foreseeable future actions have been identified upstream of the ranch that would, when combined with this project, alter hydrology in the Piute-Eldorado Valley. This alternative would have no measurable cumulative effects on regional hydrology.

Mitigation measures are not recommended for this resource.