Table 3 - 2. Climate Conditions in IRWD Service Area (2020-2025)
Annual Precipitation (inches)
Average Air Temperature (°F)
Year
Annual ETo (inches)
2025 2024 2023 2022 2021 2020
52.4 49.6 48.5 56.9
7.01
63.4 62.8 61.8 63.6 63.6 63.4
17.63 23.47
9.33 7.14
58.06
55.1
17.76
Table 3 - 3. IRWD Average Climate Conditions by Month (January – June)
Month (Averaged Values 2020-2025) Jan Feb Mar Apr May Jun Monthly Average ETo (inches) 2.5 3 3.8 4.8 5.4 6.1 Monthly Average Precipitation (inches) 2.1 2.7 3.1 1.1 0.3 0.1 Average Temperature (°F) 55.9 56.3 56.4 60 63.2 67.4
Table 3 - 4. IRWD Average Climate Conditions by Month (July – December)
Month (Averaged Values 2020-2025) Jul
Aug Sep Oct Nov Dec
Monthly Average ETo (inches) 7.04 6.7
4.9 0.2
3.9 0.4
2.9 1.4
2
Monthly Average Precipitation (inches) 0.1
0.2 2.4 Average Temperature (°F) 71.2 73.2 71.2 66.2 60.3 56.2
3.5 Historic, Current and Projected Land Use
The majority of the original agricultural lands within IRWD’s service area have been converted to residential, commercial, industrial, and other urban uses. The majority of the development within the IRWD service area follows the City of Irvine General Plan, first adopted in 1973, and subsequent amendments since then. The remainder of the land use in IRWD’s service area follows the appropriate jurisdictional agency's General Plan, supplemented with information from the County of Orange. These plans establish a guideline for land use development within the IRWD service area and serve to coordinate the timing of future growth.
Land Use Major Changes Over Time
In 1999, the Marine Corps Air Stations (MCAS) located at the eastern (El Toro) and western (Tustin) portion of IRWD closed as part of the Federal Base Realignment and Closure process. Redevelopment and reuse plans for both bases were prepared by the various jurisdictional
3 - 6
IRWD – 2025 Urban Water Management Plan
Powered by FlippingBook