Since 2012, Ameren Missouri has demonstrated that our coal combustion residual (CCR) management and disposal activities do not pose an adverse risk to public health and the environment. Reports have been prepared for all of Ameren Missouri's energy centers and each of the reports holds additional useful information about the local environment.
Ameren voluntarily participates in annual surveys regarding potential climate change risks including those related to water resources. In 2018, Ameren engages an independent engineering firm to produce a Water Resiliency Report to assess water availability in our region and the Powder River Basin, a key portion of our supply chain. That report is available here.
Since the 1970s, ash basins have been categorized as water treatment facilities and as such are subject to Clean Water Act (CWA) requirements and state-administered permitting programs. The CWA regulates discharges into surface waters (not groundwater) and publicly owned treatment works. Industrial facilities such as power plants that discharge directly into surface waters must obtain and comply with NPDES permits and facility-specific pollutant discharge limits. Ameren's ash basins at each of its energy centers are all lawfully permitted by MDNR and discharges from those basins into surface waters are specifically authorized by permit. The permits not only contain very specific conditions that must be met, but also monitoring and reporting requirements that apply to the discharge. Over the last decade, state environmental agencies began requiring groundwater monitoring and all of Ameren's energy centers now have monitoring requirements included in state operating water permits.
In Missouri, water quality is guarded through protection standards developed by state regulators. With respect to surface water, numerical limitations are placed in discharge permits as required by federal law. Effluent discharges into surface waters from Ameren's ash basins are all subject to numerical limits. Groundwater is also subject to state protection standards for specific constituents and uses. MDNR assigns "designated uses" to state water bodies, such as drinking water supply, irrigation, livestock and wildlife protection, and recreation. MDNR then designates water quality criteria to protect such uses. Ameren monitors water quality at its energy centers by sampling groundwater through a system of onsite wells and surface water discharges from ash basins. Ameren reports sampling data directly to MDNR as required by its permit. In issuing permits, MDNR provides detailed descriptions and analysis of water quality requirements and facility operations. Permits for all of our energy centers are posted on MDNR's website.
Separate from state water permit obligations, we collect groundwater data as required under the federal CCR Rule, which imposes detailed requirements including specific public reporting obligations. Consistent with those requirements, we have installed monitoring wells up- and down-gradient of CCR basins, which provide regular sampling for the presence of specific coal ash constituents. Data is collected over several years to account for seasonal variations and will be used to establish protection standards through a statistical analysis protocol. Due in part to background levels and site specific geochemistry, these protection standards can differ among energy centers. We continue to collect and evaluate data to calculate the applicable protection standards required by the CCR Rule. Monitoring data collected in 2017 and the statistical analysis methodology used by Ameren are available here.
Ameren continues to collect data, including sampling to determine the nature and extent of any groundwater impacts. Once those efforts are complete, Ameren will prepare reports that analyze the data and outline the extent of any observed impacts and appropriate corrective measures. We anticipate completing those reports during the second quarter of 2019, after which we will host meetings to take public comments from interested stakeholders.