Caltrans Stormwater WQ Handbook, Maintenance Staff Guide (2009), Section C.23.2 Infiltration Basins, specifies measures intended to maintain infiltration basins as effective devices, and set forth inspection and maintenance procedures to allow the basins to function as designed for water quality purposes. This guidance includes inspections, preventive maintenance, and maintenance. Observations are made at various times of the year to inspect for standing water, erosion, vegetation type and presence, sediment accumulation. CASQA BMP Handbook, TC-11, Operation and maintenance guidelines. Observations are made after storms, and at the end of the wet season, and include observations of standing water, accumulated sediment, trash and debris, and vegetation cover and type. Caltrans will initiate maintenance based on the results of these required condition assessments. BMPs will be maintained by Caltrans using a vactor truck, hand crews to remove excess sediment.

Caltrans intends to inspect these basins in accordance with the combined protocols described in the BMP RAM User Manual V2 (2ND Nature 2015), CASQA BMP Handbook TC-11 (Infiltration Basin) and Caltrans Storm Water Quality Handbook, Maintenance Staff Guide (2009). The primary measure of effectiveness is infiltration through observation of standing water and sediment accumulation. Although the Caltrans Maintenance Staff Guide is followed by maintenance staff and contains the most stringent inspection and maintenance protocols, only the required inputs into BMP RAM using the inspection data sheets will be submitted to the BMP RAM Online Tool. Both the CASQA and Caltrans inspection and maintenance procedures should be considered acceptable equivalents, and are sufficient for Caltrans NDPES permit. These inspections are used to assess condition/performance and initiate maintenance. Inspections of the BMPs will take place annually during spring, summer or fall.

Please see Catchment Registration Memo for complete detail