Water Resources Research Act Program

Details for Project ID 2015CO308B

Combined Influences of Hydrologic Connectivity and Nutrient Uptake on System-scale Retention

Institute: Colorado
Year Established: 2015 Start Date: 2015-03-01 End Date: 2016-02-29
Total Federal Funds: $5,000 Total Non-Federal Funds: $2,435

Principal Investigators: Tim Covino

Abstract: The U.S. spends >$1 billion a year on river restoration [1], yet there is increasing evidence that water quality is on the decline [2]. River restoration often strives to maximize nutrient retention and enhance water quality by reconnecting rivers to their floodplains. Sub-surface (hyporheic) and surface (slower flowing channels, eddies, and pools) retention zones have the capacity to increase nutrient retention through extended interactions between water, sediment, and microbes that enhance nutrient uptake [3-4]. In theory, for nutrient retention to be maximized at the system-scale (103 m), retention zones must have sufficient hydrological connectivity (rate of water and nutrient exchange) with the advective main channel [5]. However, the role of hydrologic connectivity on system-scale nutrient retention remains an open question in watershed hydrology and biogeochemistry. To address this gap, we will assess the relative contributions of local (100-102m) nutrient uptake dynamics and hydrologic connectivity on system-scale retention in an active beaver meadow in the North Saint Vrain (NSV) Watershed, CO. Beaver meadows are multithreaded riparian wetland environments that substantially influence catchment hydrologic and sediment transport dynamics [8], biogeochemical cycles [9], and habitats [10]. Notably, beaver meadows have been demonstrated to be highly resilient to drought [11], floods and wildfires [12]. While considerable research has identified local influences of beaver dams on storage and flux dynamics, few studies assess the system-scale effects of serial beaver impoundments. Thus, our research should not only provide fundamental insights into system-scale retention, but should bolster the science necessary to better inform beaver reintroduction as a river restoration tool.