The Conservation District performs occasional maintenance of its facilities as such maintenance becomes necessary. The District has an Operations and Maintenance Manual to guide these efforts. These facilities can be broken up into the following categories:
Access Roads – Roads are typically 12-15 feet wide and surfaced with native material such as gravel or compacted soil. Activities include clearing encroaching vegetation, filling ruts and potholes, grading, resurfacing (with similar materials), and repairing washouts. Vegetation control usually occurs annually, and other activities usually occur every 2-3 years.
Canals – Canals are typically dug into the existing topography and are left with their natural surface. Depending on the canal, the bottom and sides of the canals may develop natural rock armor over time, as the fine material is washed away, or may experience sedimentation. Activities include clearing encroaching vegetation, removing sedimentation, and repairing washouts or erosion. Washout and erosion repair is typically accomplished by filling in the eroded area with native material and sometimes grouted rock. Vegetation control usually occurs annually, and other activities occur infrequently.
Culverts – Typically, pipe or box culverts are used to pass water in a canal under a road crossing. Activities include clearing encroaching vegetation, clearing of debris or sediment in the nearby canal, and repairing damage to the nearby canal or the culvert itself. Repair of the nearby canal is due to erosion or washout of the canal sides above or below the structure, and such repair is typically accomplished by filling in the eroded area with native material and sometimes grouted rock. Repairing the culvert itself typically requires excavation of the roadway. Vegetation control usually occurs annually, sediment removal every 2-3 years, and the remaining activities infrequently.
Dikes – Dikes are typically comprised of native material from which much of the rock has been removed and formed into a berm about 5-15 feet high. Native vegetation is left to grow on the slopes of dikes. Water is passed from one basin to the next through overflow culverts, typically constructed of corrugated metal pipe with a concrete headwall, that then pass through the dikes. Activities include occasional excavation and compaction of the dike material at the source of leaks, similar work to replace broken overflow culverts, and repair of washouts. Such repairs occur infrequently.
Recharge Basins – Basins are typically areas of shallow excavation on the upstream side of dikes and are where the actual water percolation takes place. Flow of water into these basins brings suspended sediment, which is dropped to the basin floor with percolation of the water. This sediment requires periodic removal, which also tills the basin floor, in order for percolation rates to remain efficient. Activities include clearing encroaching vegetation and removal of sediment. Vegetation control usually occurs annually, and sediment removal occurs every 1-5 years depending on the basin, storm intensity, and other variables. Sand, silt, and other materials removed from the basins are stockpiled and may be screened or processed before removal from the property. The processing and removal are often subcontracted to outside organizations.
Diversion Structures – These structures divert water from the river or creek into the canals or from the canals into the basins. The diversion structures typically consist of concrete or cement block with wooden gates and associated hardware. Activities include clearing encroaching vegetation, clearing of debris or sediment from the nearby river, creek, or canal, repair of the nearby canal, and repair of damage to the structure itself. Repair of the nearby river, creek, or canal is due to erosion or washout of the soft plugs, weirs, or canal sides above, below, or around the structure, and such repair is typically accomplished by filling in the eroded area with native material and sometimes grouted rock. Vegetation control occurs annually, removal of sediment occurs every 2-3 years depending on use and weather, and all other activities occur infrequently.
Invasive Plant Removal – The District staff, often in cooperation with the Inland Empire Resource Conservation District, identify and remove invasive plants from the districts’ properties. Often basins are not significantly impacted because they are often submerged for weeks or months and this operation controls the weedy invasive species; however, canals, the perimeter of basins, and other open space areas are subject to invasive species. Species removed include Tamarisk (Salt Cedar), Arundo Donax (Giant Cane), castor bean, Stinknet (Glove chamomile), Stinkwort (Dittrichia graveolens), and other invasives in the areas of these species. Invasive grasses are a significant issue in some areas which will be addressed through the Habitat Conservation Plan developed as part of the Wash Plan.