Integrating Temporal Inequality into Conservation Planning to Improve Practice Design and Efficacy. (11th June 2018)

• Record Type: Journal Article
• Authors: Williams, Mark R.; King, Kevin W.; Penn, Chad J.
• Is Part Of: Journal of the American Water Resources Association. Volume 54:Number 5(2018:Oct.)
• Page Start: 1039
• Page End: 1054
• Publication Date: 2018-06-11
• Subjects: Lorenz curve -- time‐series -- edge‐of‐field -- water quality -- subsurface drainage -- surface runoff; Water-supply -- Periodicals; Hydrology -- Periodicals; Water resources development -- Periodicals; Water resources development -- Environmental aspects -- Periodicals; 333.9100973
• DOI: 10.1111/1752-1688.12662
• Languages: English
• ISSNs: 1093-474X

Abstract

Abstract: In contrast to spatial inequality, there are currently no methods for leveraging information on temporal inequality to improve conservation efficacy. The objective of this study was to use Lorenz curves to quantify temporal inequality in surface runoff and tile drainage, identify controls on nutrient loading in these flowpaths, and develop design flows for structural conservation practices. Surface runoff ( n = 94 site‐years) and tile drainage ( n = 90 site‐years) were monitored on 40 fields in Ohio. Results showed, on average, 80% of nitrate‐nitrogen, soluble reactive phosphorus (P), and total P loads occurred between 7 and 12 days per year in surface runoff and between 32 and 58 days per year in tile drainage. Similar temporal inequality between discharge and load provided evidence that loading was transport‐limited and highlighted the critical role hydrologic connectivity plays in nutrient delivery from tile‐drained fields. Design flow criterion for sizing structural practices based on load reduction goals was developed by combining Lorenz curves and flow duration curves. Comparing temporal inequality between fields and the Maumee River, the largest tributary to the western Lake Erie Basin, revealed challenges associated with achieving watershed load reduction goals with field‐scale conservation. In‐field (i.e., improved nutrient and water management), edge‐of‐field (i.e., structural practices), and instream practices will all be required to meet nutrient reduction goals from tile‐drained watersheds. Abstract : Research Impact Statement : Results provide a framework to incorporate temporal inequality into the conservation planning process and improve the design of structural conservation practices in tile‐drained landscapes.