In our region and elsewhere, there are substantial water withdrawals for drinking water, power generation, and agriculture along rivers. There are increasing impacts of salt pollution from watersheds related to winter road deicers, wastewater inputs, chemicals added during water treatment, fertilizers, and weathering of impervious surfaces. Over the past century, there have been increasing trends in salt ions in streams, rivers, and lakes across the U.S., which includes major drinking water supplies. At the same time, there are increasing impacts of salinization extending landward from sea level rise and salt water intrusion. The convergence of salinization from both directions due to changes in winter climates, extreme storm events, and saltwater intrusion can affect clean drinking water, aquatic life, the salt front of tidal rivers, and major consumptive uses of water in Maryland. In addition, the increasing salinity of non-tidal and tidal waters can also influence water quality by not only the salt ions themselves but indirectly through the metals, nutrients, and other contaminants mobilized by increased salinization. Salinization is a major threat globally, and its impacts are increasing regionally and locally in Maryland with changes in land use, population, and climate.
Activities
Although efforts have been placed on collecting extensive data sets on specific conductance (a proxy for salinity), less work has focused on analyzing and mapping salinization trends extensively in Maryland along non-tidal streams and tidal rivers and drinking water supplies and translating results to stakeholders. In addition, there is a need to develop robust proxies for widely measured specific conductance data to convert to concentrations of ions and secondary contaminants mobilized by salts. Given the widespread proliferation of conductivity sensors, the development of proxies and relationships to convert these high-frequency sensor measurements to chemical concentrations would represent a valuable tool to management and regulatory agencies. For example, development of these proxies and relationships can help understand and predict if and when critical thresholds for infrastructure, aquatic life, and drinking water are exceeded by salinity now and in the future. They will also help us understand the increasing magnitude and scope of impacts associated with freshwater salinization and saltwater intrusion in watersheds.
Engagement with Stakeholders
This work would build on and greatly expand existing relationships with stakeholders at Maryland Department of the Environment, Maryland Department of Natural Resources, Washington Metropolitan Council of Governments, and U.S. Environmental Protection Agency (EPA). From MDE, the Chief of the Watershed Restoration Planning Division has visited us at UMD, and has expressed interest in working together on outreach products.. MDE started a salt training program for Maryland salt applicators. We also have started conversations with the Source Water Protection and Water Appropriations Division at MDE regarding tidal rivers and impacts of salinization on water intakes. We reviewed a report by Maryland DNR on salinization impacts on aquatic life in Maryland, and are also in touch with him and could work on thresholds. Finally, we have ongoing collaborations with Washington Metropolitan Council of Governments regarding salinity issues.
We are also involved in a salt technical working group sponsored by Washington Suburban Sanitary Commission (WSSC) involving a variety of stakeholders at state and county levels. We have also solicited input on Grand Challenges from U.S. EPA Region3 and Office of Research and Development. These stakeholders have expressed interest in the development and current need for salinization risk maps, sensor proxies for salt ions and secondary contaminants, and decision support tools and fact sheets translating research into salt management.
Products and Tools
We plan to develop proxies for converting sensor measurements to concentrations of different salt ions (and contaminants mobilized by salinization) for different waters in the Chesapeake Bay region. This will be a first step in converting and interpreting simple and widespread measurements of electrical conductivity by sensors and probes into concentrations of salty chemicals of concern. We will also provide maps of trends along impacted streams and rivers in Maryland and development of proxies for predicting salt concentrations and associated contaminants of concern. These salt risk maps extending from headwaters to tidal waters and salt proxies calibrated for waterbodies do not currently exist. We would plan to disseminate information through fact sheets. We could also work with UMD water quality extension on outreach videos (we’ve discussed that in the past but been limited by time and resources). We could work with MDE on a module for their salt training certification program (we’ve talked about that in the past too but have been limited by time and resources). We could organize or co-organize a targeted state and local workshop regarding salinization impacts – please see an example of a national and international workshop on tidal rivers.
Experiential Education
Graduate and undergraduate student participation in field monitoring and sampling, laboratory measurement, data analysis, and engagement with stakeholders.
