Common problems and how to troubleshoot them for tree trenches and tree boxes
Link to this table

Symptom Possible causes Solution
Storage system overflows or high flow activator engages often Stored water is not being used up enough Increase usage of water and/or empty storage before a large storm event.
Excessive sediment build-up inside the storage tank Pretreatment is not working, first flush diversion is not working Check that the pretreatment BMPs and first flush diversion is working as intended. Check whether conditions changed in the contributing area. Install source control BMPs as needed.
Water smells foul Growth of algae or microbes inside the tank Drain and clean the tank, replace or backwash any filters
Clogging of intake and filters in the first flush diversion system Too much fine debris is accumulating. This can be particularly a problem during the spring pollen season or fall leaf-off season Clean and replace filters as needed, clean or sweep contributing areas more often.
Area around storage tank is wet or humid There may be a leak Check tank for any leaks and repair.
Erosion or scouring along the diversion pathways Overflow is activated too often or receiving area is not appropriate for the overflow Stabilize the eroded area and vegetate any bare spots. Add erosion control measures as needed (rip rap, check dams, level spreaders, etc.) Correct for drainage and flow path issues to make sure flows are evenly distributed. Make sure the flow paths are unobstructed. Make sure that the storage is being drawn down sufficiently often, and particularly before any heavy storms.
Excessive mosquitos in or around the storage unit The screens may be ripped. Check and replace the mosquito screens.