Year Established: 2016 Start Date: 2016-03-01 End Date: 2018-02-28
Total Federal Funds: $29,922 Total Non-Federal Funds: $74,556
Principal Investigators: Robert Payn
Abstract: The new Montana State Water Plan recommends strategies that improve “natural water storage”, particularly in alluvial wetlands and shallow aquifers (DNRC, 2015). The authors of the plan contend that enhancing natural storage will “support late season (stream) flows, help to mitigate the impact of drought cycles, and provide environmental benefits” (DNRC, 2015). This contention is strongly dependent on natural storage that has sufficient volume, residence time,and loss efficiency to be meaningful late in the dry season under Montana’s increasingly arid conditions. We therefore propose that study of these hydrologic characteristics of natural storage in alluvial systems is critical to effective implementation of the state water plan. Beaver-mimicry restoration (BMR) seeks to simulate the natural effects of beaver activity in streams, and has become a popular approach to hydrologic reconnection of stream channels to floodplain and riparian systems (Pollock et al., 2015). Proponents of BMR and authors of the State Water Plan suggest that restoration of incised streams will improve stream and riparian habitat, improve water quality (e.g., reduce excess sediment and nutrient loads), reduce stream temperatures in the summer, and improve natural seasonal storage in wetlands and local alluvial aquifers. The influences of BMR on biological aspects of ecosystem recovery have been well documented (Pollock et al., 2015). However, the effects of BMR on natural water storage and stream temperatures have not been adequately tested, and thus the specific hydrologic mechanisms that would promote higher and cooler late summer flows remain poorly understood. Furthermore, the potential for consumption due to higher evapotranspiration rates offsetting the benefits of enhanced natural storage has not been investigated. These key gaps in understanding prevent a quantitative basis for the use of BMR as a viable strategy for drought resiliency planning and management of cold-water fisheries.