EBTAG Annual Workshop and Field Trip
May 16-17, 2012

Amy C. Lewis, Hydrology and Water Planning, 7 Seton Plaza, Santa Fe, NM, 87508, amychilderslewis@earthlink.net

The impact of management alternatives on the hydrology and soils in the Upper Santa Fe Watershed were analyzed using a series of analytical and empirical tools. The USFS is proposing to conduct a prescribed fire within a 2,900-acre area of the Santa Fe River municipal watershed located in designated Wilderness of the Santa Fe National Forest for the purpose of reducing the risk of a high-intensity fire. The potential sediment yield and peak flows were estimated for existing conditions, under the worst-case scenario in which a catastrophic fire consumes the entire area (8,500 acres); and for a prescribed fire in the proposed action area (2,900 acres).

To develop a range of estimates for sediment yields and peak flows, several models were used and compared to empirical methods. The conclusion was that a catastrophic fire followed by intense rainfall events could result in damaging peak flows, impair the storage capacity and water quality of the municipal reservoirs. Predicted sediment yields and peak flows resulting from the proposed action are insignificant and pose no threat to the water storage and treatment systems or to the ecosystem.