1. What is the MPEP?

The Management Practices Evaluation Program, or MPEP, is a required component of the Central Valley Regional Water Quality Control Board Irrigated Lands Regulatory Program. The MPEP will evaluate and demonstrate which agricultural management practices are effective in protecting water quality, and how these practices have been or will be implemented to minimize nitrate leaching to groundwater. A Workplan describing activities to be completed as a part of the MPEP received Conditional Approval from the Central Valley Regional Water Quality Control Board in May 2017.

2. Why is the MPEP important?

The Central Valley Regional Water Quality Control Board is obligated by law to develop and issue permits (referred to as Waste Discharge Requirements) to potential sources of water pollution, in order to protect those waters for specified uses (including drinking water and irrigation of crops). The MPEP is one of several required actions in the permits issued to Central Valley irrigators. The penalties for failing to comply with these permits vary, but they include large fines and/or orders to cease operations.

On the positive side, the MPEP is the part of the permit that allows growers to demonstrate that they are protecting water quality as part of their operations, and (as a result) to avoid more cumbersome requirements that are designed to curb ongoing, unabated pollution. This type of demonstration is the main goal of the MPEP, and should limit the long-term costs to comply with these permits.

3. Is the MPEP just about nitrate?

The current focus is on minimizing nitrate leaching, but the overall Irrigated Lands Regulatory Program also pertains to other constituents that could be construed as pollutants (e.g., sediment in runoff, salts). If at some point other constituents need to be addressed by growers, the MPEP would likely serve the same functions for those constituents.

4. Is this all because of the Harter Report?

The Harter Report was one of several lines of evidence that supported the expansion of the Irrigated Lands Regulatory Program to limit losses of applied nitrogen into underlying groundwater.

5. What geographic areas are involved?

The Southern San Joaquin Valley MPEP includes areas within the Buena Vista Coalition, Cawelo Water District Coalition, Kaweah Basin Water Quality Association, Kern River Watershed Coalition Authority, Kings River Watershed Coalition Authority, Tule Basin Water Quality Coalition, and Westside Water Quality Coalition. These coalitions are organized as the SSJV MPEP Committee (Committee). The Committee is also working with other water quality coalitions implementing an MPEP in other areas of the Central Valley. At the moment, the MPEP is only required to be carried out in high-vulnerability areas, but results are applicable on all irrigated lands.

6. Does the MPEP require grower reporting?

No, the MPEP has no specific grower reporting requirement. The MPEP may, however, use anonymous information collected as part of the Nitrogen Summary Report and Farm Evaluation to make sure that growers’ operations are correctly represented.

7. How long will the MPEP continue?

The permit allows 8 years for development of the MPEP, including 2 years for work planning and 6 years for implementation of the first phase. This timeframe began in January 2016. While this appears to be a long period, it is worth noting that most growers select practices annually, so modifications often take a year to implement and more time to assess. Over a duration of only 6 to 8 growing seasons, substantial planning, investigation, interpretation, outreach, and implementation must occur. In addition, implementation progress is required to be assessed and reported.

8. How much does the MPEP cost and who is paying for it?

The MPEP is a grower-directed program, so program activities and therefore the cost, will depend on what the coalitions decide is necessary and helpful to their growers. In pennies per acre, the MPEP costs grower-members about 8 cents/acre-year. However, the coalitions were recently awarded $2M through a USDA NRCS Conservation Innovation Grant. This grant award, combined with match contributions exceeding $2M, provides part of the funding necessary for successful implementation of the MPEP. In addition, the coalitions are pursuing funding from other sources, including the CDFA Fertilizer Research and Education Program (FREP).

9. What technical partners are supporting the MPEP?

The coalitions are collaborating with several technical partners, including the USDA NRCS, the CA Department of Food and Agriculture, and the University of California Cooperative Extension.  These partners will help to plan technical approaches, identify known, protective practices, assess and quantify fate and transport through modeling, work with cooperating growers, perform focused field studies, explain sound practices to growers and their advisors, and develop information and tools that facilitate application of practices that protect groundwater quality.

10. What if the State changes the requirements?

There will almost certainly be some changes over time. However, coalitions are working with the Regional and State water boards to maintain the most important and useful parts of the permits, and to limit new elements that threaten grower confidentiality, add new and cumbersome processes, monitoring, or reporting, or that are otherwise unworkable or unhelpful. We think that when we comply with our existing permits, and strive to make and document rapid progress through processes like the MPEP, that this makes our case stronger in claiming that the current permit conditions need not be changed or augmented.

11. Isn't it dangerous to assess our own performance? Isn't that the State's job?

The orders require that growers assess their own performance. This is common in environmental programs, partly because the owner of a business or operator of a facility knows so much more about how to best to maintain and improve environmental performance. The Central Valley Regional Water Quality Board usually sets up the framework of the program or permit, and then works with the permit holders to make sure that the goals of the program are met as the operation works within that framework.

12. What crops are included in the MPEP?

All crops irrigated for commercial purposes are included in the MPEP, except for those included under other permits, such as rice, alfalfa hay and silage. The MPEP will prioritize groups of crop, soil, and groundwater conditions, focusing on situations with the greatest potential to minimize nitrate leaching.

13. How does the MPEP account for soil variability?

The most detailed soil data that is readily available comes from NRCS’ soil surveys, which are now available digitally. This allows the data to be efficiently incorporated into landscape-level (considering many, diverse fields at once) assessments in computer models (also developed with NRCS as a major supporter). By using this soil information, estimates of water amount and quality as it moves through soils will reflect soil properties to the greatest extent practicable with current technology.

Landscape-level results will be compared to runs of more detailed, site-specific measurements and modeling results. The landscape-level model will then be adjusted as necessary to improve these estimates.

14. Is it mainly a bunch of new studies, field monitoring, monitoring wells, modeling, or what?

The schedule does not allow for complete dependence on new studies, since they take several years to develop and complete. Fortunately, FREP, UCCE, commodities groups, USDA, and many others have been studying efficient use of N fertilizer for some years. The focus will be on ensuring that this knowledge is available and useful to growers, on encouraging or doing high-priority new work, and on using available information to assess how practices affect groundwater. The assessment will involve modeling that is rigorously checked against field observations. Where groundwater quality data are needed, observations from existing wells will be used to the maximum extent possible, but some new monitoring wells may also be needed.

15. Will the MPEP include monitoring wells?

The focus of the program is on understanding what happens in the soil and how it relates to management practices. This usually requires measurements closer to the surface, in the crop root zone. Monitoring wells are rarely used for this purpose because groundwater quality does not tell us enough about where a contaminant came from or, if it happened to come from an agricultural field, why it was leached from the soil. A few monitoring wells may need to be installed, but will be kept to the bare minimum necessary to meet regulatory requirements.

Groundwater data will be needed to understand long-term trends in groundwater quality. These data may be from samples taken in existing wells managed by others, those shared with other groups who need to monitor groundwater, or a few that coalitions install wells to answer a specific question that cannot be addressed another way. The coalitions will handle this “Groundwater Trend Monitoring” separately from the MPEP.

16. Will the MPEP include field studies?

The agricultural research community has been working on soil fertility and efficient use of nitrogen for decades, producing a great deal of useful information that needs to be assimilated into the performance assessment and outreach parts of the program. After all, using existing knowledge gets quicker results, and allows us to focus new studies (there are a couple) on pressing questions for which answers are as yet unclear. This approach is consistent with a widely accepted standard for scientific inquiry: begin by understanding what is already known, then frame a new and relevant question before launching into costly experimentation.

17. Will the MPEP include individual field sampling?

No, it is quicker and less costly to work with growers to use data that they already have about their management and fields than to collect new data. However, field sampling may occur as a part of a limited number of field studies (see #16).

18. How will the MPEP relate management practices to groundwater quality?

This is one of the most challenging parts of the program and it requires bringing several approaches together to answer the question. First, root zones that produce very little leaching nitrate cannot reasonably be assumed to be big sources of nitrate going to groundwater. Therefore, understanding what is happening to water in the root zone, before it moves downward toward groundwater, is crucial. Aquifers are large, and reflect the combined influence of many individual fields. One-by-one evaluation of fields is therefore unnecessary and unhelpful. We are using a landscape-level model, in which the individual fields are broken into classes with similar management, crop, and soil characteristics. The performance of each class is analyzed, and then these effects are applied to the locations where these classes have been mapped. The results characterize a reasonably accurate representation of the true pattern of water and nitrate emanating from root zones, which is the type of input needed to understand how underlying groundwater will be affected.

Second, relatively simple groundwater quality calculations can be made, considering the amount of water and nitrate that are recharging from irrigated lands and other sources. The results can help to predict further groundwater quality trends.

Third, groundwater quality trends can be measured directly in existing or new wells, so that this is another requirement in the Central Valley Irrigated Lands permits. To achieve this goal efficiently, Coalitions are working together and with neighbors and partners to develop a regional well network, utilizing existing wells wherever possible.

19. What about other sources of pollution besides irrigated crops?

The landscape-level model used to assess management practices (see #18) will incorporate other nitrate sources, such as industrial, dairy, and septic systems, so that water quality relationships of irrigated lands are assessed in a realistic context.

20. Will the MPEP identify specific fields as sources of nitrate leaching?

No. The MPEP is not focused on assessing individual fields, but rather on assessing the performance of classes of management practices, crop, and soil combinations over time. The results of these assessments will be made available to growers to help them to assess their own performance. If these large-scale assessments suggest that the combination of management practice, crop, and soil that comprise your field tends to produce more nitrate leaching than alternatives, then you will be able to compare these results to several alternative suites of practices.

21. What about all the improvements growers have already implemented related to management of agrichemicals and water?

The MPEP recognizes that existing management practices already include the careful use of crop and soil information to determine appropriate nitrogen rates, and careful handling and application of fertilizer to ensure that it is taken up by the crop. A major goal of the MPEP is to understand and include these approaches in the required performance assessments. This should result in recognition of existing cropping systems that are already protective of groundwater, and expansion of these approaches where this could provide even broader benefit.

22. Will the MPEP specify a set of required management practices?

No, the MPEP’s purpose is not to mandate specific practices. We know that growers need flexibility to adapt practices to their specific situation, whether that be the nature of their operation, the soil they farm on, or the commodity that they grow. The MPEP is designed to preserve this flexibility to the maximum extent possible. Rather than prescribing, the approach is similar to that employed by NRCS and Cooperative Extension: practices are related to specific performance objectives and field situations, and then the grower can fashion a solution that fits their operation. The difference is that there will be even more focus on the pollutants that the Central Valley Regional Water Quality Board is most concerned about, and right now that is mainly nitrate.

It is possible that in specific areas, certain management practices will be encouraged, or even required as part of Groundwater Quality Management Plans that the Central Valley Regional Water Quality Control Board also requires of coalitions. The MPEP aims to minimize these types of requirements by getting out ahead of them with good performance, and with evidence of that good performance.

23. Where can I find information on management practices that minimize nitrate leaching?

To start sharing information as quickly as possible, the coalitions compiled numerous resources at http://agmpep.com/. The site includes a calendar of outreach events related to nutrient management, hosted by a wide variety of entities. The site also includes a directory of publicly available agricultural management practice tools and resources. The directory is an evolving collection of resources, and is not intended to be comprehensive, or to replace site-specific management recommendations.

In addition, and as results of the MPEP become available, the coalitions will be using many other methods of communication to share results with growers, including grower meetings, focused mailings, and online tools.

24. Can I help in some way?

A grower-led effort is developing to gather agronomic, management, and soil data from a large number of production fields. Data can be from any time during the past ~10 years. These data will be associated with a soil type and then anonymized, and will serve to help understand the relationship of N fate to management, as well as to check and improve modeling inputs and outputs. If you are interested in learning more about this, then please send email to agoutreach@plantierra.com.

25. What if I have a question or suggestion?

Please contact your coalition, or send input to agoutreach@plantierra.com, if you have a question or suggestion related to the MPEP.