Discharge monitoring and priority reporting on Central Valley dairies
A Central Valley dairy is designed not to discharge manure or process wastewater to streams, canals or drains. When something does leave the property — storm water from a field, tailwater at the end of an irrigation run, or wastewater from a failed pipe — the dairy order requires two things: measuring what was discharged and telling the right agencies quickly. This guide explains both, based on the Monitoring and Reporting Program of Order R5-2013-0122.
This is a summary for general information, not legal advice. In an actual incident, follow the dairy's own order and contact the Regional Water Board.
What counts as a discharge
The order distinguishes several situations, each with its own rules:
- Manure or process wastewater from the production area to surface water — prohibited.
- Storm water from the production area to surface water — prohibited; the production area must contain it.
- Storm water from land application areas to surface water — prohibited from fields that received manure or wastewater unless the field has been managed consistently with a certified nutrient management plan; such discharges are monitored.
- Tailwater — irrigation water leaving the lower end of a field — subject to monitoring when the field received manure or wastewater in the previous 60 days.
Monitoring a discharge
Wastewater or manure discharges
If manure or process wastewater reaches surface water, the discharge itself is sampled and analysed for a broad list of constituents: nitrate-nitrogen, total ammonia and un-ionized ammonia, total Kjeldahl nitrogen, total phosphorus, potassium, total dissolved solids, five-day biochemical oxygen demand, total suspended solids and total and fecal coliform. In addition, for each day the discharge continues, the receiving water is measured upstream — just far enough not to be influenced — and downstream, where the discharge has mixed: field readings of conductivity, temperature, dissolved oxygen and pH, and laboratory analyses for the nitrogen forms, phosphorus, potassium, solids and coliforms.
Storm water from the production area
For any day storm water leaves the production area for surface water, the dairy records the date, time, approximate volume, duration, location, source and destination, and samples the discharge and the receiving water upstream and downstream. Field measurements cover conductivity, dissolved oxygen, temperature, pH and ammonia; laboratory analyses cover nitrate-nitrogen, turbidity, total phosphorus and total and fecal coliform.
Storm water from land application areas
Each year, storm water discharges are sampled from one third of the land application areas — one field for a dairy with one to three, two for a dairy with four to six, and so on — at two moments: the first storm of the wet season that produces significant runoff, and a storm during the peak of the season, typically February, after at least three dry days, within the first hour of discharge. The record includes volume, duration and destination; samples are measured in the field for conductivity, temperature, pH and ammonia, and analysed for nitrate-nitrogen, total phosphorus, turbidity and coliforms. If conditions are too dangerous to sample, the dairy documents why and samples once it is safe.
Tailwater
For every tailwater discharge from a field irrigated less than 60 days after manure or wastewater was applied, the dairy records the date, time, approximate volume in gallons, duration and destination, and takes field readings. The first such discharge of the year is also analysed in a laboratory for nitrate-nitrogen, total phosphorus and coliforms.
Priority reporting of significant events
Some events cannot wait for the annual report. The order requires a dairy to report, within 24 hours of becoming aware of it, any noncompliance that endangers human health or the environment, and any violation of the order's main discharge prohibitions. All intentional or accidental spills are reported under this provision.
Who is told
The report goes to three places: the Central Valley Water Board office, the county's environmental health department, and the state's emergency management agency, which the 2013 order calls CalEMA and which is now the California Governor's Office of Emergency Services (Cal OES). Its warning centre operates 24 hours a day. Outside business hours, a message is left on the regional board's voicemail giving the time, date, place and nature of the event and the name and number of the person reporting, and the call is recorded in writing.
The written report
Within two weeks, a written report goes to the regional board. It describes the noncompliance and its cause, its duration, when compliance was or will be restored, and the steps taken or planned to prevent it from happening again. The order lists what it must contain, including:
- the date, time and location, the destination of any unauthorised discharge and its flow path to a receiving water;
- a description of the event and its cause;
- the flow rate, volume and duration of the discharge;
- the rainfall, in inches, on the day of the discharge and on each of the seven days before;
- details of the samples taken, the field measurements and the analyses requested.
The rainfall requirement is a good reason to keep a rain gauge on the dairy and read it daily in the wet season.
The annual storm water report
Storm water monitoring results are also summarised in the annual report due each 1 July, including a summary of all storm water discharges from the production area to surface water during the year. Inspection logs, discharge records and laboratory reports filed together through the year make that section straightforward to prepare.
Preparing before the rain
Most discharges are prevented, or caught early, by the routine visual inspections, by keeping freeboard in the ponds ahead of the wet season, and by planning irrigation so that tailwater does not leave fields that recently received manure. Having sample bottles, a cooler, a field meter, the laboratory's address and the reporting numbers in one place — the emergency tab described in our emergency planning guide — saves precious time when it rains hard at night.
Sources
- Central Valley Regional Water Quality Control Board, Order R5-2013-0122, prohibitions and Monitoring and Reporting Program: Table 3 (discharge monitoring) and section C, "Priority Reporting of Significant Events".
- California Governor's Office of Emergency Services, Cal OES, State Warning Center.