Environmental Enforcement Monitoring at the Food-Water Interface: Measuring Regulatory Land Management Performance with Comparative Integrated Hydrologic Simulations

Environmental monitoring tools are diverse and numerous, but typically include direct measurements of environmental state variables using mobile or stationary instruments or sampling of environmental phases (air, water, etc.) for lab analysis. Some environmental outcomes related to specific regulated parties cannot be monitored directly and are therefore difficult to enforce. Enforcement may instead be in form of prescribing often inflexible - best management practices (BMPs), as is common, for example, in agricultural groundwater use and pollution. Its large spatial extent leads to diffuse, non-local environmental impacts. Here, we introduce the use of comparative integrated hydrologic simulation tools that measure sustainable water management outcomes of land use practices in food production for regulatory enforcement. We present two novel cases, a simulation tool for monitoring stream depletion due to groundwater pumping and a simulation tool for monitoring long-term future groundwater quality outcomes from nitrate pollution. Monitoring in both applications is by attribution to specific land management practices and their outcomes (stream depletion, water quality degradation/improvements). Performance is measured by quantifying the difference between simulated land management practice scenario outcome and simulated outcomes of a reference land management practice (e.g., natural, unimpaired, or business-as-usual). Attribution of environmental outcomes with hydrologic simulation tools provide opportunities for more targeted environmental enforcement and for consideration of complex environment-land use-climate interactions, without constraining regulated parties to often expensive and inflexible BMPs. The simulation approach to monitoring diffuse environmental outcomes provides opportunities for incentivizing creative management solutions, but also more transparency. The approach holistically integrates a wide range of available environmental and land use data by appropriately reflecting those in the built and calibration of the hydrologic simulation tool. Challenges in application of such tools include buy-in from stakeholders to non-traditional monitoring tools. This requires engagement, outreach, and learning with and by stakeholders.