Abstract

Abstract:

Stoneman Lake is one of 2 natural lakes in the state of Arizona. Occasionally, this lake experiences such severe drought, that the lakebed becomes completely dry. Adjacent to the lake basin, a ditch exists that could be reopened in order to divert additional volume to the lake. Stoneman Lake homeowners have asked me to determine maximum carrying capacity of the ditch, as well as volume added in response to the 50-Year and 100-Year events for a 24-hour storm. These storms were modeled using the Army Corps of Engineers Hydrologic Engineering Center – River Analysis System (HEC-RAS), and the Hydrologic Engineering Center – Hydrologic Modeling System (HEC-HMS).

The current maximum carrying capacity of the ditch is 45 cubic feet per second if left as is. There exists the potential to double this flow if the ditch is restored. Using parameters from an adjacent watershed, volume contributions were determined. If additional runoff is allowed to enter the lake basin via the ditch, a total volume of 314 acre-feet and 396 acre-feet is added to the lake during the 50-year and 100-year event respectively. Lake rise depends on a starting lake elevation. The maximum rise in lake elevation is 4 feet for the 100-year storm.