The idea for the research proposed here originated from discussions between DR

The Environmental Protection Agency Region 8 awarded North Dakota State University $398,200 under the Regional Wetland Program Development Grants program (CFDA 66.461) on May 15, 2021 for a project concluding on December 31, 2024. The funding supports research to evaluate the effectiveness of constructed wetlands in reducing sediment and nutrient loads to improve water quality within 303(d)-listed watersheds in North Dakota. Specifically, the university will analyze what size, depth and design of constructed wetlands would be needed to lower pollutant loads below thresholds over the long term without other mitigation measures or land use changes. The results seek to determine the limits of using constructed wetlands alone to improve watershed water quality, which could guide wetland programs across the United States.

Marinus otte (north dakota state university, ndsu), DR. Donna jacob (houston engineering INC, HEI), and MR. Aaron larsen (north dakota department of environmental quality, nddeq) about what information relating to water quality and wetlands was lacking and needed to be addressed with the highest priority in north dakota. The state has lost at least 45% of its WETLANDS1, but IT is as high as 90% in other REGIONS2,3,4, and loss of wetlands is continuing in the US and around the WORLD5. As a result, an incalculable value of ecosystem services, such as sediment and nutrient retention and hydrological buffering have been LOST6. However, IT is also recognized that construction of new wetlands can offset losses &ndashand the trend in the US over the period of 2004-2009 showed no discernible loss in freshwater wetlands, mainly because construction of new wetlands offset losses of natural wetlands to agricultural, industrial and urban DEVELOPMENT5. A problem identified as needing highest priority in north dakota is reduction of sediments and nutrient loading (&lsquoandloads & rsquoand) to 303(d)-listed WATERSHEDS7, many including reservoirs. Most of the reservoirs were created to reduce downstream flooding and as drinking water supply and to support recreational activities. An approach of interest to north dakota would be to incorporate constructed wetlands into impacted watersheds with a view to lower loads. This would also have added benefits in terms of other ecosystem services provided by wetlands, such as provision of habitats and hydrological buffering. IT is well known that wetlands are very effective in removing sediments and nutrients from WATER8, 9, 10, and guidance on how to incorporate wetlands into systems to improve water quality has been in existence for decades, also from the US EPA11. The main question that the proposed project aims to answer is: can wetlands be constructed within 303(d)-listed watersheds in north dakota to significantly reduce total maximum daily loads (tmdls) to improve water quality? The idea to incorporate constructed wetlands in the landscape to improve water quality of entire watersheds is not NEW12. A good example of integration of constructed wetlands into a small watershed is that of the anne valley project on integrated constructed wetlands in IRELAND13, which was initiated in the 1990S14. An example also exists from north dakota, where wetlands were constructed in the bowman-haley reservoir watershed in conjunction with buy-INS from landowners to the conservation reserve program, and where loads were reduced SUCCESSFULLY15. A more recent example is provided by friendsofreservoirs.COM in their guidance on use of wetlands for mitigation of EUTROPHICATION16, which includes an example from a watershed in nebraska. Another example of restoration and construction of wetlands in a watershed, in this case primarily for hydrological reasons, is the tongue river project in northeastern ND17. However, while guidelines exist about how to design and size wetlands to reduce pollutant concentrations in specific waste WATERS18, no studies have been reported to answer the question how much wetland (size, depth, design) would be needed to reduce the loads of entire watersheds to below acceptable thresholds over long periods of time, absent any other mitigation measures and changes in land uses within the watershed. In other words, is IT possible to drastically improve the water quality of a watershed if only the area of wetlands would be increased? This is of importance, not just for north dakota, but for the entire US and beyond, because IT will determine the limits of constructing wetlands for water quality improvement of watersheds. Are there any situations where construction of wetlands suffices to improve water quality within watersheds or are changes in land uses necessary as well in most cases? Converting an entire watershed