Evaluation of Freshwater Provisioning for Different Ecosystem Services in the Upper Mississippi River Basin: Current Status and Drivers

Abstract

With the high demand for freshwater and its vital role in sustaining multiple ecosystem services, it is important to quantify and evaluate freshwater provisioning for various services (e.g., drinking, fisheries, recreation). Research on ecosystem services has increased recently, though relatively fewer studies apply a data driven approach to quantify freshwater provisioning for different ecosystem services. In this study, freshwater provisioning was quantified annually from 1995 to 2013 for 13 watersheds in the Upper Mississippi River Basin (UMRB). Results showed that the annual freshwater provision indices for all watersheds were less than one indicating that freshwater provisioning is diminished in the UMRB. The concentrations of sediment and nutrients (total nitrogen, and total phosphorus) are the most sensitive factors that impact freshwater provisioning in the UMRB. A significant linear relationship was observed between precipitation and freshwater provisioning index. During wet periods freshwater provisioning generally decreased in the study watersheds, primarily because of relatively high concentrations and loads of sediment and nutrients delivered from nonpoint sources. Results from this study may provide an insight, as well as an example of a data-driven approach to enhance freshwater provisioning for different ecosystem services and to develop a sustainable and integrated watershed management approach for the UMRB.

Evaluation of Drought Implications on Ecosystem Services: Freshwater Provisioning and Food Provisioning in the Upper Mississippi River Basin

“…The FWP is affected by both flow and water quality, with water quality having a greater influence [ 43 ]. As shown in Figure 8 a–f, the total flow decreased in most drought years and increased in most wet years in each subbasin.…”

“…Although the streamflow increased in wet years, the reduced water quality condition in the same period may result in a reduction of FWP . On the other hand, the decreased streamflow in drought years may not reduce the FWP because of the improved water quality condition during the same period [ 7 , 8 , 43 ]. As a result, the annual FWP displayed a weak correlation with both drought indices ( SPI 12 and SSI 12) in HUCs0707, 0709, 0711, and 0714, indicating that the annual freshwater provisioning is less affected by precipitation or streamflow deficits and/or surplus in these subbasins.…”

“…The freshwater provisioning indicates the quantity of freshwater that can be provided for multiple uses (drinking, fisheries, recreation, and survival conditions for aquatic lives) in the case that water conditions simultaneously meet the environmental flow requirements and water quality standards [ 43 ]. The freshwater provisioning ( FWP ) and freshwater provisioning index (FWPI) at both seasonal and yearly scales were calculated from 1985 to 2014 for 14 HUC4 subbasins based on SWAT outputs of daily streamflow and water quality concentrations of TN , TP , and TSS .…”

“…Consequently, the MF EF used in this study was 30% of average annual flow. Two seasonal environmental flow values (October–March and April–September) for qne calculation were determined as 10% of average seasonal flow [ 4 , 43 , 44 ]. According to State Nutrient Reduction Strategy documents and water quality criteria in different ecoregions proposed by the Environmental Protection Agency (EPA) [ 45 ], the water quality standards of TN , TP , and TSS adopted in this study were 3 mg/L, 0.1 mg/L, and 38 mg/L, respectively.…”

Surface Depression and Wetland Water Storage Improves Major River Basin Hydrologic Predictions

“…Although hybrid models that integrate physical processes and data-driven statistical regression may simulate nutrient removal and decay in lakes and reservoirs (e.g., SPAtially Referenced Regression On Watershed (SPARROW) attributes model; Robertson & Saad, 2014), inclusion of millions of small depressional storage systems-even through a parsimonious approach (section 2.3.3)-would likely change existing water quality assessments. The overall changes in water quality projections from depression-integrated models would therefore likely impact environmental 10.1029/2019WR026561 Water Resources Research sustainability decisions (Fant et al, 2017;Li et al, 2016Li et al, , 2017Yen et al, 2016) including estimates of watershed-scale ecosystem services, applicable best management practices, and the economic consequences of both across the world's major river basins (Golden et al, 2017).…”