Human amplified changes in precipitation–runoff patterns in large river basins of the Midwestern United States

Abstract

Abstract. Complete transformations of land cover from prairie, wetlands, and hardwood forests to row crop agriculture and urban centers are thought to have caused profound changes in hydrology in the Upper Midwestern US since the 1800s. In this study, we investigate four large (23 000-69 000 km 2 ) Midwest river basins that span climate and land use gradients to understand how climate and agricultural drainage have influenced basin hydrology over the last 79 years. We use daily, monthly, and annual flow metrics to document streamflow changes and discuss those changes in the context of precipitation and land use changes. Since 1935, flow, precipitation, artificial drainage extent, and corn and soybean acreage have increased across the region. In extensively drained basins, we observe 2 to 4 fold increases in low flows and 1.5 to 3 fold increases in high and extreme flows. Using a water budget, we determined that the storage term has decreased in intensively drained and cultivated basins by 30-200 % since 1975, but increased by roughly 30 % in the less agricultural basin. Storage has generally decreased during spring and summer months and increased during fall and winter months in all watersheds. Thus, the loss of storage and enhanced hydrologic connectivity and efficiency imparted by artificial agricultural drainage appear to have amplified the streamflow response to precipitation increases in the Midwest. Future increases in precipitation are likely to further intensify drainage practices and increase streamflows. Increased streamflow has implications for flood risk, channel adjustment, and sediment and nutrient transport and presents unique challenges for agriculture and water resource management in the Midwest. Better documentation of existing and future drain tile and ditch installation is needed to further understand the role of climate versus drainage across multiple spatial and temporal scales.

Flow, Flux, and Feeding in Freshwater Mussels

“…It is relevant that the ability of unionid mussels to discriminate among algae in rivers decreases with algal flux because of increased base flows, peaks flows, and rising limbs in rivers that have been affected by climate change, agricultural land use practices, and urbanization (Foufoula-Georgiou et al, 2015;Kelly et al, 2017;Trudeau & Richardson, 2015. Given that the nutritional value varies among algae (e.g., Bartsch et al, 2017;Gatenby et al, 1997), it is reasonable to postulate that a reduction in the ability to discriminate among algal species may have negative implications for the long-term growth and survival of unionid populations.…”

The Power of Environmental Observatories for Advancing Multidisciplinary Research, Outreach, and Decision Support: The Case of the Minnesota River Basin

“…Hydrologic changes within a watershed can lead to a complex response in the channels and channel networks with potential negative repercussions on erosion, transport of sediment and pollutants, and ecosystem integrity (e.g., Blann et al, 2009;Konar et al, 2013;Schilling et al, 2008;Vörösmarty & Sahagian, 2000). The MRB is particularly sensitive to hydrologic change, with deeply incised tributaries eliciting a strong geomorphic response to ongoing changes in hydrology Call et al, 2017;Foufoula-Georgiou et al, 2015;Gran et al, 2013;Kelly et al, 2017). This makes it a valuable location to systematically investigate linkages between changes in the landscape and river ecohydrologic and morphologic response.…”

“…There are three main reasons for this: (1) Large-scale conversion of prairie to primarily row-crop agriculture with accompanying changes in surface and subsurface drainage has left the MRB strongly altered from its pre-European settlement state, affecting its connectivity and hydrologic response (Figures 2a and 2b;Foufoula-Georgiou et al, 2015;Lenhart et al, 2012;Schottler et al, 2014). Analyses of available discharge, precipitation, and land use/land cover data have demonstrated increasing flows over time on the mainstem Minnesota River and its tributaries Kelly et al, 2017;Novotny & Stefan, 2007); (2) The deeply incised postglacial valleys are particularly sensitive to changes in hydrology, and the strong geomorphic response in channels has important ramifications for erosion and sediment loading Cho, 2017;Gran et al, 2013;Lauer et al, 2017;Lenhart et al, 2018;Vaughan et al, 2017); and (3) Dramatic increases in fertilizer input, coupled with the drainage of~80% of historic wetlands in the region since European settlement, have contributed to high loads of nitrogen and phosphorus throughout the watershed creating numerous local and downstream water quality challenges, including drinking water contamination, algal blooms, hypoxic zones, and harm to aquatic life (Boardman, 2016;Hansen et al, 2018;USACE, U.S. Army Corps of Engineers St. Paul District, M, 2004).…”

“…The MRB has experienced increasing flows over the past few decades (Kelly et al, 2017;Novotny & Stefan, 2007;Schottler et al, 2014) as well as changes in the hydrologic response, such as altered hydrograph shapes and reduced water residence times . River channels naturally increase in width and depth to accommodate such increases in flow, but the partitioning Figure 1 for location of Greater Blue Earth River Basin within the Minnesota River Basin.…”

The Need for an Integrated Land‐Lake‐Atmosphere Modeling System, Exemplified by North America's Great Lakes Region

“…In recent decades a panoply of such changes have been documented: a statistically significant warming trend (Schoof, 2013;Zobel et al, 2017Zobel et al, , 2018, an increase in extreme summertime precipitation (Kunkel et al, 2003(Kunkel et al, , 2012, extreme changes in lake levels (Gronewold et al, 2013), and a reversal of the increasing trends in lake-effect snows (Bard & Kristovich, 2012;Clark et al, 2016;Kunkel et al, 1999;Norton & Bolsenga, 1993;Notaro et al, 2013;Suriano & Leathers, 2017). More recently, the region has also seen changes in the quantity and timing of extreme precipitation and runoff, which have important implications for flooding, soil erosion, nutrient export, and agricultural best management practices (Carpenter et al, 2017;Kelly et al, 2017).…”