The Ground Maintenance Department is responsible for the maintenance and improvement of over 1,070 linear miles of earthen and concrete-lined drainage channels, 37 stormwater detention basins, numerous flood control structures, bridges, gates. Our maintenance activities also include mowing, tree management, herbicide application in ROW, and the removal of sediment and foreign materials that build up in our channels.
General Guidelines for Inspection and Maintenance of Stormwater Drainage Infrastructure
Inspection and maintenance of stormwater control facilities, such as retention/detention basins and earthen drainage channels are necessary to ensure that these facilities are in good condition and operating as designed to manage and/or convey stormwater runoff. Drainage infrastructure is inspected routinely during normal conditions and during storm events when stormwater is present and being conveyed through drainage channels and basins and detention/retention facilities. General maintenance items are included below for drainage channels.
Earthen Drainage Channel Maintenance
- Vegetation Management – Overgrown vegetation has the potential to obstruct stormwater flow and reduce the carrying capacity of the channel. Inspections are conducted routinely to verify that vegetation growth is kept to 24 inches or less. Mowing is generally required when grasses and vegetation exceed 24 inches in height. Sufficient grassy vegetation should be established within the drainage channel to prevent erosion.
– If grass coverage is sparse and erosion is evident, native grass seed will be distributed in bare areas to encourage growth and stabilization.
- Presence of debris – Excessive debris accumulations will be removed from drainage channels.
Detention/ Retention Basin Maintenance
- Vegetation Management – Overgrown vegetation has the potential to obstruct stormwater flows and reduce the design capacity of the basin. Inspections shall be conducted routinely to verify that vegetation growth is kept to 24 inches or less. Mowing is generally required when grasses and vegetation exceed 24 inches in height. Woody vegetation such as trees and large shrubs should not be evident in basins and should be removed if observed. Sufficient grassy vegetation should be established within the basin to prevent erosion.
– If grass coverage is sparse and erosion is evident, native grass seed should be distributed in bare areas to promote vegetation coverage and stabilization.
- Sediment Accumulations – Routine inspections will be conducted to verify that the basin outlet and areas immediately downstream are free of significant sediment accumulations.
– Removal of sediment and accumulated material from the basin may be required if significant sediment accumulations are evident and reduce the capacity and functionality of the basin. If sediment accumulations are removed, it may be necessary to re-seed the disturbed area with a native grass seed mix.
- Obstructions – The inlet and outlet structures of the basin are inspected routinely to look for signs of erosion or obstructions.
- Presence of debris – Excessive debris shall be removed from basins.