District Size: 34,880 acres Year Formed: 1958 Projects: Air Quality Concerns:
Recent agreements with the Environmental Protection Agency (EPA) and the San Joaquin Valley Unified Air Pollution Control District (UAPCD) coupled with these agencies surging interest in agricultural activities have brought the air quality issue to the attention of the Columbia RCD. Fugitive Dust relating to agricultural operations and Noxious Gases relating to confined animal operations are areas of interest.
Soil Concerns:
Erosion: The Columbia RCD supports activities that will reduce erosion on the nearly level and level lands in the area. Conservation measures that will reduce wind and water erosion are encouraged. Conservation practices that will reduce sheet and rill erosion on areas in native vegetation also should be addressed.
Nutrient Depletion: The Columbia RCD supports activities that are developed and practical for the reduction or elimination of nutrient depletion from the soils.
Salinity/Alkalinity: As Irrigation management becomes more efficient, problems related to increasing concentrations of salts in the crop root zone become more prevalent. As less water is used, and the return systems allow the reuse of the excess water collected, salts can increase to critical levels and cropping changes may be needed or alternate techniques of leaching maybe recommended.
Water Concerns:
Groundwater Depletion/Recharge: In general three different conditions within and adjacent to the Columbia RCD influence groundwater depletion/recharge. These are: I) surface water deliveries and supplemental groundwater pumping in the Columbia CC service area within the Columbia RCD, 2) groundwater pumping east of the Columbia CC service area within the Columbia RCD on lands that do not have surface water entitlements and 3) groundwater pumping and a cone of depression east of the Columbia RCD in Madera County.
Groundwater/Surface Water Quantity/Quality: The salinity of the groundwater generally increases to the southwest in and near the Columbia Canal Co. service area. West of Mendota Dam and west of Firebaugh, high salinity groundwater is present in the Sierran Sands. However, east of the San Joaquin River, groundwater is of relatively low salinity in most of the upper aquifer. However, chloride and boron concentrations in water from some wells are at or near values that can adversely affect some types of crops.
Most of the good quality groundwater in the area was recharged from groundwater inflow from the northeast, seepage from the San Joaquin River, and from deep percolation and canal seepage in areas irrigated with good quality canal water for many years. The TDS of water from most irrigation wells in Columbia RCD ranges from about 100 to 500 ppm.
Under natural conditions, groundwater flowed towards the trough of the valley from both the east and west. The Columbia RCD is located east of this trough (the San Joaquin River). There is a concern that the reversed groundwater flow direction, now to the northeast, could eventually result in deterioration of the quality of the groundwater near and east of the valley trough. This has already been observed near Mendota and in the Firebaugh Canal Company service area, west of the Columbia RCD.
Yields of many irrigation wells in the area range from about 1,000 to 2,500 gpm, and specific capacities average about 55 gpm per foot of drawdown.
Surface/Irrigation Water management/Availability: With the costs of pumping groundwater ever increasing due to the lowering of the water table and the rising cost of energy. There will he continued demand for assistance to the landowners for managing irrigation water better. Assistance available will include; irrigation water scheduling, crop water usage, soil permeability and depth of penetration, land leveling information and the value of irrigation return systems.
Flooding: The area along the San Joaquin River, in the western part of the Columbia RCD is subject to flooding during high runoff years. Thee Columbia RCD continues to support embankment maintenance activities needed to prevent periodic flooding and will work with the Army Corps of Engineers and other public agencies in flood control/prevention.
Vegetation Concerns:
Land Use: About 80 percent of the area is used to produce agricultural crops. Native vegetation is found in the eastern part of the RCD and riparian vegetation exists along the San Joaquin River channel.
Invasive Species: There is concern about riparian plant species that could impact agricultural productivity.
Animals Concerns:
Domestic Stock: There is increasing concern regarding dairy operations as they relate to water issues.
Wildlife: The Columbia RCD supports biodiversity balance within the area. Overview: Landowners and Managers in the Columbia Resource Conservation District (Columbia RCD) are conscious of the need for and the benefits of Conservation practices including but not limited to farm, range open space, urban development, wildlife, recreation, watershed, water quality, woodland; best adapted to save the basic resource, soil, water and air of the state from unreasonable and economically preventable waste and destruction. It is realized that to be truly effective, group participation and action over multiple ownership is also necessary.
Land form:
Columbia RCD lands consist of alluvial areas on the San Joaquin Valley basin and basin rim. Lands consist of level to nearly level areas located within the drainage of the San Joaquin River and Fresno Slough.
Climate:
The climate in the vicinity of the Columbia RCD is characterized by cool winters and long, hot summers. July is the warmest month with an average maximum temperature of about 98 degrees F. Daytime summer temperatures frequently exceed 100 degrees F. Daytime winter temperatures average about 54 degrees F with nighttime lows averaging about 36 degrees F. Nighttime winter temperatures may fall below freezing as a result of infrequent cold spells. The frost-free growing season averages about 290 days.
The 30-year normal annual precipitation at Mendota Dam during the period 1961 through 1990 averaged 7.54 inches. About ninety percent of the annual precipitation occurs during the six-month period November through April. Measurable precipitation may fall during any month of the year; however, summer rainfall is infrequent.
Soils:
Soils in the vicinity of the Columbia RCD arc predominately those of the Columbia--Temple and Traver-Chino Associations. The soils in these associations are typically used and well suited for the production of irrigated field/row forage and vegetable crops.
All agricultural soils have potential management problems and the primary considerations associated with the use and management of these soils include the moderate coarse texture, imperfect drainage, and excess salinity/alkalinity.
Groundwater pumping for irrigation has lowered the water table and improved drainage conditions compared to natural conditions. Problems associated with the use and management of these soils include the moderate coarse texture, and excess salinity/alkalinity.
Leaching to maintain a favorable salt balance and irrigation water management are significant considerations for maintaining crop yields in Columbia RCD. Rice was grown in past years for purposes of reclaiming saline/alkaline soils and is currently planted on a limited acreage on finer textured saline/alkaline soils. The native salinity/alkalinity along with the salinity additions associated with the applied irrigation water require that a leaching fraction be applied during the normal course of irrigation to maintain soil salinity levels at some predetermined level.
Irrigation management must address the moderate coarse textured soils which often require additional irrigation applications during the growing season because of lower moisture holding capacity when compared to finer textured soils. Crops with shallow root zones (i.e. beans and onions) require careful irrigation management to maintain soil moisture levels needed to achieve maximum production potential.
Watershed:
The Columbia RCD is within the watershed areas of the San Joaquin River and Fresno Slough. Irrigation tailwater is collected and reused for irrigation through a system of surface drains and on-farm tail water collection/reuse facilities along with tailwater relift stations. Any excess surface drainage from irrigation not reused for irrigation is generally discharged into the San Joaquin River. These discharges to the San Joaquin River are infrequent. Lands in native vegetation on the eastside of the Columbia RCD naturally drain into sloughs and creeks in the area. These flows historically drained into the San Joaquin River prior to the development of agriculture in the area.
Woodlands:
Woodlands do not occur within the Columbia RCD boundary. The only wooded areas in the vicinity are associated with the riparian habitat areas adjacent to the San Joaquin River channel. About 30 percent of the Columbia RCD in the northeast part of the area has not been developed and remains in native vegetation.
Wildlife:
Wildlife found in the vicinity of the Columbia RCD is typical to the San Joaquin Valley including birds (waterfowl, upland game birds and various other bird species) and fur bearing mammals (coyotes, possums, raccoons, etc.)
