Precipitation, runoff, and water loss in the lower Colorado River–Salton Sea area

A preliminary water balance for the Colorado River delta, 1992–1998

“…This study estimates runoff at 8% of precipitation, to account for the lack of rainfall records for the mountain regions balanced against expected infiltration in the permeable alluvial soils between the base of the mountains and the hydrologic systems in this study. Accurate projections of runoff require records of finer temporal resolution than were available for this study, as well as analysis of the permeability of soils underlying ephemeral streams (Hely & Peck, 1964). Therefore, the calculations of tributary runoff are offered as a general estimate.…”

“…As noted, some (10 7 m 3 year -1 ) of this water discharges to El Doctor wetlands through artesian springs (Glenn et al, 1996). Factors such as soil depth and permeability, vegetative cover, and rainfall intensity and duration affect runoff (Hely & Peck, 1964). Hely & Peck (1964) estimated runoff for the lower Colorado River-Salton Sea area, roughly 50 -100 km north of the study area, by measuring initial soil infiltration and correlating this with soil type to project a runoff curve number.…”

“…Factors such as soil depth and permeability, vegetative cover, and rainfall intensity and duration affect runoff (Hely & Peck, 1964). Hely & Peck (1964) estimated runoff for the lower Colorado River-Salton Sea area, roughly 50 -100 km north of the study area, by measuring initial soil infiltration and correlating this with soil type to project a runoff curve number. This runoff curve was then used to project runoff as a percentage of precipitation, ranging from effectively 0% for sandy alluvial soils, to roughly 8% for less permeable alluvial soils, to more than 20% for foothill/plateau areas with less permeable soils.…”

“…For flood years, ∆S a was calculated from extent of inundated area and reported infiltration rates for the permeable alluvial soils characteristic of the floodplain. Measured initial infiltration for dry or slightly moist soils was reported at 2.5 cm for a 30 minute period (Hely & Peck, 1964).…”

Groundwater Availability Within the Salton Sea Basin Final Report

“…For example, Hely and Peck (1964) provided maps of interpolated precipitation, evapotranspiration and runoff rates for the periods October-April and May-September based on weather data collected over a 30-year period between 1931 and 1960. Because of their age, these maps cannot be easily transferred to today's conditions considering land use changes and possible trends in the local weather conditions.…”