Operation and maintenance for stormwater and rainwater harvest and use/reuse
This site will be developed in Fall, 2016
Overview of Operation and Maintenance of Stormwater Harvesting and Use Systems
While many stormwater systems are designed to be relatively passive with minimal oversight needed, harvesting and use systems require managed operation where the goal is to move water from the storage unit to a point of use so that there is sufficient storage available to receive runoff from subsequent rainfall events. The timing and management of the water storage and use operation needs to be integrated into the system design. With an actively managed operating system, regular maintenance is also important to preserve the end use water quality, maintain system safety and efficiency, and minimize costs associated with repairs and downtime.
Operation and Maintenance Agreements
Stormwater harvesting and use systems rely heavily on being properly operated and maintained and therefore having a formal agreement in place upfront is critical. An operation and maintenance agreement should:
- clearly state the responsibilities of the owner in operating and maintaining the system,
- describe the technical ability of the owner to perform the operation and maintenance,
- verify that a third party providing O & M services is approved by the city (or other local jurisdiction),
- address how the transfer of responsibilities will be managed should ownership change in the future, and
- provide for an on-going Operation and Maintenance Plan as described below.
Operation and Maintenance Plans
In general, stormwater harvesting and use O & M plans should include the following items:
A. Site plans showing:
- Location of system components
- Maintenance access points for all functional elements of the system
- Location and type of all operational controls (pumps, valves, sensors, etc.)
- Location of underground utilities
B. As-built drawings showing:
- Layout of pipes
- Location of all controls
- Location and type of all components that require periodic replacement (e.g. filters)
C. Operation and troubleshooting guidelines for system controls including:
- Distribution systems (pumps, valves, sensors, etc.).
- Treatment systems (monitoring requirements, dosages, etc.)
- Overflow and bypass systems (valves, water level sensors, etc.).
- Applicable regulations
D. Statements describing when a licensed/certified professional is needed for repair or maintenance of tanks, pumps, pipes, controls, or other components.
E. Description and schedule of inspection activities for all system components including
- Spring start-up and winter decommissioning
- Regular inspections – annual, seasonal, monthly, etc.
- Inspection guidelines for special circumstances (very large runoff events, electrical outages, etc.)
- Safety protocols to be followed during inspection
F. Description and schedule of maintenance activities for all system components including
- Spring start-up and winter decommissioning
- Regular maintenance – annual, seasonal, monthly, etc.
- Replacement schedule for control elements of system (rain sensors, level loggers, pumps, etc.)
- Safety protocols to be followed during maintenance
G. Manufacturer’s literature for all controls, replaceable components, and prefabricated components (pumps, sensors, treatment components, prefabricated storage units, etc.).
H. Component-specific O&M plan details
- Collection surfaces
- Sweeping schedule for paved surfaces
- Collection and pre-treatment system
- Instructions for correct operation of any manual valves
- Location and type of filters
- Location of debris collection sumps
- Storage system
- Cleaning schedule
- Statement describing the method and frequency of water level monitoring
- Treatment system
- Point of use water quality criteria/standards
- Schedule of required water quality monitoring
- Inspection schedule for all treatment components, per manufacturer’s guidelines
- Schedules for cleaning of filters, replacement of chemicals, etc.
- Safety protocols including special or hazardous materials handling
- Requirements regarding how long a storage unit should flush out in the spring before irrigation or other end uses begin so high chloride levels don’t kill vegetation or corrode metal components
- Distribution system
- Instructions for correct operation of any manual valves
- Required color coding or labeling of pipes carrying harvested water
- Backflow preventer maintenance and inspection requirements
- Irrigation system (if applicable)
- Controller programing guidelines
- Irrigation map showing application rates appropriate for soils/plantings
- Any Material Safety Data Sheets (MSDS) that are relevant for operation
- Inspection requirements for all components of the system
- Assumption used in sizing the system
- Applicable laws, codes and permits
I. Monitoring Plan
- Use rates should be monitored at least monthly for at least three years. This should be compared to the water budget analysis of the design to determine whether the modeled level of performance is being achieved.
- Required water quality monitoring
J. Inspection forms/maintenance logs for all regularly scheduled inspection and maintenance activities.
K. Statements outlining the roles and responsibilities of all parties participating in the operation, monitoring, and maintenance of the system, including which party must follow up on items that are outside the normal operating procedures.