Mono Basin: Sierra Gauged Runoff

Vorster estimates that Sierra Gauged Runoff typically amounts to 150 KAF/yr. This flow is comprised mainly of five streams with the following mean average flows:
  • Rush Creek
61 KAF/yr (see photo 4.2 in the book)
  • Lee Vining Creek
49 KAF/yr
  • Mill Creek
22 KAf/yr
  • Walker Creek
5 KAF/yr
  • Parker Creek
8 KAF/yr

Vorster combines the flows from these streams with the flows from other, smaller, gauged streams that provide aqueduct or irrigation supply. The estimate of 150 KAF/yr is an average of runoff over the time interval from 1937 to 1983.

The width of the Sierra Gauged Runoff arrow in the sketch on the previous page portrays the relative size of the flow. Don't pay too much attention to the actual direction of the flow. (The five streams flow in an easterly or northeasterly direction rather that the southeasterly direction in the sketch.)

The flow records show considerable variability from one year to another. For example,
    in 1983, Sierra Gauged Runoff was at 289 KAF/yr, almost twice as large as the average value
   in 1977, on the other hand, the flow was gauged at 65 KAF/yr, around 43% of the average flow.

Around two-thirds of the years have exhibited a flow ranging from 69% to 131% of the average flow.

The diversion points for the City of Los Angeles are located on these gauged streams. Water diverted to LA is called "export" in Vorster's model and in chapter 4. Water that is not diverted toward LA is then free to reach Mono Lake and mix with its saline waters.

More Details on the Export:

Pages 136-137 of Vorster's Thesis describes the "Surface Water Export" from the creeks that comprise "Sierra Guaged Runoff." Vorster explains that "The diversion facilities on Lee Vining, Walker and Parker Creek consists of small checkdams that divert the creek flow into the Lee Vining conduit; the conduit in turn empties into the northwest corner of Grant Lake Reservoir." Vorster gives a sketch of the conduit leading to Grant Lake on page 128, but the sketch is somewhat difficult to interpret. For a larger portrayal of the creeks, the conduit, Grant Lake, and the export you may turn to the LADWP website:

http://web.ladwp.com/~wsoweb/Aqueduct/realtime/monorealtime.htm

As of Dec 11, 2000, this website provided a clear picture of the creeks and the conduit, and it gave LADWP "real time" measurement of the flows.