Multiple models guide strategies for agricultural nutrient reductions

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Using a Multi-Institutional Ensemble of Watershed Models to Assess Agricultural Conservation Effectiveness in a Future Climate

This study investigates the combined impacts of climate change and agricultural conservation on the magnitude and uncertainty of nutrient loadings in the Maumee River Watershed, the second-largest watershed of the Laurentian Great Lakes. Two scenarios — baseline agricultural management and increased agricultural conservation — were assessed using an ensemble of five Soil and Water Assessment Tools driven by six climate models. The increased conservation scenario included raising conservation adoption rates from a baseline of existing conservation practices to feasible rates in the near future based on farmer surveys. This increased adoption of winter cover crops on 6%–10% to 60% of cultivated cropland; subsurface placement of phosphorus fertilizers on 35%–60% to 68% of cultivated cropland; and buffer strips intercepting runoff from 29%–34% to 50% of cultivated cropland. Increased conservation resulted in statistically significant (p ≤ 0.05) reductions in annual loads of total phosphorus (41%), dissolved reactive phosphorus (18%), and total nitrogen (14%) under the highest emission climate scenario (RCP 8.5). While nutrient loads decreased with increased conservation relative to baseline management for all watershed models, different conclusions on the true effectiveness of conservation under climate change may be drawn if only one watershed model was used.publishedVersio

Comparing two tools for ecosystem service assessments regarding water resources decisions

We present a comparison of two ecohydrologic models commonly used for planning land management to assess the production of hydrologic ecosystem services: the Soil and Water Assessment Tool (SWAT) and the Integrated Valuation of Ecosystem Services and Tradeoffs (InVEST) annual water yield model. We compare these two models at two distinct sites in the US: the Wildcat Creek Watershed in Indiana and the Upper Upatoi Creek Watershed in Georgia. The InVEST and SWAT models provide similar estimates of the spatial distribution of water yield in Wildcat Creek, but very different estimates of the spatial distribution of water yield in Upper Upatoi Creek. The InVEST model may do a poor job estimating the spatial distribution of water yield in the Upper Upatoi Creek Watershed because baseflow provides a significant portion of the site’s total water yield, which means that storage dynamics which are not modeled by InVEST may be important. We also compare the ability of these two models, as well as one newly developed set of ecosystem service indices, to deliver useful guidance for land management decisions focused on providing hydrologic ecosystem services in three particular decision contexts: environmental flow ecosystem services, ecosystem services for potable water supply, and ecosystem services for rainfed irrigation. We present a simple framework for selecting models or indices to evaluate hydrologic ecosystem services as a way to formalize where models deliver useful guidance

Evaluating the Impact of Legacy P and Agricultural Conservation Practices on Nutrient Loads from the Maumee River Watershed

The recent resurgence of hypoxia and harmful algal blooms in Lake Erie, driven substantially by phosphorus loads from agriculture, have led the United States and Canada to begin developing plans to meet new phosphorus load targets. To provide insight into which agricultural management options could help reach these targets, we tested alternative agricultural-land-use and land-management scenarios on phosphorus loads to Lake Erie. These scenarios highlight certain constraints on phosphorus load reductions from changes in the Maumee River Watershed (MRW), which contributes roughly half of the phosphorus load to the lake’s western basin. We evaluate the effects on phosphorus loads under nutrient management strategies, reduction of fertilizer applications, employing vegetative buffers, and implementing widespread cover crops and alternative cropping changes. Results indicate that even if fertilizer application ceased, it may take years to see desired decreases in phosphorus loads, especially if we experience greater spring precipitation or snowmelt. Scenarios also indicate that widespread conversions to perennial crops that may be used for biofuel production are capable of substantially reducing phosphorus loads. This work demonstrates that a combination of legacy phosphorus, land management, land use, and climate should all be considered when seeking phosphorus-loading solutions

The Wabash Sampling Blitz: A Study on the Effectiveness of Citizen Science

The increasing number of citizen science projects around the world brings the need to evaluate the effectiveness of these projects and to show the applicability of the data they collect. This research describes the Wabash River Sampling Blitz, a volunteer water-quality monitoring program in Central Indiana developed by the Wabash River Enhancement Corporation (WREC). Results indicate that field test strips for nitrate+nitrite-N read by volunteers generally agree with lab-determined values. Orthophosphate results are less transferable owing to low observed concentrations, although the field test strip values from unfiltered samples consistently over-predicted the lab values. Hierarchical cluster analysis (HCA) applied to volunteer-collected data groups sampling sites into meaningful management clusters that can help to identify water-quality priorities across the watershed as a proof of concept for watershed managers. Results of the HCA provide an opportunity for WREC to target future programs, education, and activities by analyzing the data collected by citizen scientists. Overall this study demonstrates how citizen science water quality data can be validated and applied in subsequent watershed management strategies

Multiple models guide strategies for agricultural nutrient reductions

For nearly twenty years in the western United States, billions of dollars have been spent to recover anadromous salmon species listed under the federal Endangered Species Act. Broad support and participation from the private and public sectors is needed to address the limiting factors to salmon viability, especially the improvement of stream and watershed health. However, in today’s fiscal and political climate it is more important than ever to demonstrate the multiple ways that conservation work benefits not just the environment but also our economy. This paper examines the employment and economic impacts of watershed restoration expenditures made in Oregon from 2001–2010, making use of multipliers developed by the University of Oregon’s Ecosystem Workforce Program. We collected data on salmon habitat restoration projects from a statewide database system, the Oregon Watershed Restoration Inventory, and grouped project activities according to the University of Oregon restoration employment and economic multiplier categories. To determine the total direct, indirect, and induced economic output and employment resulting from restoration investments, we multiplied the total project investment in each category of restoration work by the relevant multiplier. We then summed the total economic activity by project type to arrive at a total per county and the state. We found that a total of US$411.4 million was invested in 6,740 watershed restoration projects throughout the state of Oregon from 2001 to 2010, resulting in the generation of between$752.4 million and $977.5 million in economic output and 4,628 to 6,483 jobs. The jobs created by restoration activities are located mostly in rural areas, in communities hard hit by the economic downturn. Restoration activities bring a range of employment opportunities for people in construction, engineering, natural resource sciences, and other fields. The job creation potential of restoration activities compared with investments in other sectors of the economy is favorable. Restoration also stimulates demand for the products and services of local businesses such as plant nurseries, heavy equipment companies, and rock and gravel companies. Unlike in other economic sectors, restoration jobs can’t be outsourced to distant locations, so these dollars tend to stay in the local and state economy. Restoration investments also continue to accrue and pay out over time. Long-term improvements in habitat create enduring benefits, from enhanced recreational and fishing opportunities to the provision of critical ecosystem services. These findings are good news to the people of Oregon and there is tremendous opportunity to extend and replicate this work to other regions. Being able to effectively communicate the interdependencies of ecosystems and economies is critical to addressing the immense challenges of the 21st century. As long as we continue to frame trade-offs in simplistic terms like jobs versus the environment, we will be relegated to making incremental change. Whether our aim is the recovery of wild salmon in the Western United States or the abatement of greenhouse gas emissions; alternative models for economic development need to be redoubled. We have found that quantifying and presenting the economic benefits of watershed restoration reframes the conversation and opens doors to new alliances