West Mojave Plan FEIR/S - Desert Managers Group

is so restrictive that project delays are common. In fact, most project proponents forego trappingand assume presence, obtain Section 2081 permits, and complete appropriate mitigation andcompensation (CDFG, pers. comm. 21 August 2002).The cost of trapping studies depends on the size of the project area, and can exceed the costto mitigate and compensate impacts. If the trapping result is negative, there is no need for issuanceof a 2081 permit; if positive, the proponent would need the take permit and pay associated costs.Although this has resulted in CDFG having to issue more permits, including projects where theMGS may not occur, there have not been substantial delays, as current staff are issuing permits in atimely manner (i.e., within a few months).3.2 AIR QUALITY, SOILS AND WATER3.2.1 Climate and Air QualityThe climate and air quality of the western Mojave Desert is discussed briefly below. Amore detailed discussion can be found in Appendix H.3.2.1.1 ClimateThe West Mojave planning area is a desert characterized by hot summer temperatures(average daily highs above 100 degrees Fahrenheit) and low annual precipitation (approximately5 inches). Snow can occur during the winter. Probably more important than the averages is theextreme variability in the weather. Daily temperatures ranges of 40 degrees can occur.Precipitation extremes are also common: variations of 80% in annual precipitation can occur.Summer thunderstorms can drop more precipitation on a site in one event than the meanprecipitation for that location. High winds can occur. Peak wind velocities above 50 miles perhour (MPH) are not uncommon and winds of 100 MPH occur every year.Temperature: Extremes of temperature are common in the planning area. Below ornear freezing temperatures are common at most weather stations. Seven of thirteen stations haveaverage low temperatures below freezing in December and January. El Mirage has the lowestaverage temperatures in the planning area and Twentynine Palms has the highest averagetemperatures. Average daily temperature variation is 29 degrees for all stations. Seasonalvariations are high. Ridgecrest, for example, has recorded highs of 118 degrees and lows of 0degrees since the middle 1980s.Precipitation: Deserts are noted for their low rainfall and the Mojave Desert is noexception. The blocking nature of the mountains on the western and southern boundaries of thedesert results in a rain shadow on the desert side of the mountains where precipitation is far lessthan on the coastal side. Weather patterns and their resulting precipitation follow the seasonalwind patterns and changes. This results in winter precipitation generally arriving from thesouthwest and spreading eastward across the desert. Winter precipitation volumes normally arethe highest in the western Mojave Desert and diminish toward the east. This is illustrated in themean precipitation for western locations such as Lancaster and Mojave (over 6 inches) andChapter 3 3-43