Best Management Practices for Diffuse Nutrient Pollution: Wicked Problems Across Urban and Agricultural Watersheds

Abstract

Extensive time and financial resources have been dedicated to address nonpoint sources of nitrogen and phosphorus in watersheds. Despite these efforts, many watersheds have not seen substantial improvement in water quality. The objective of this study is to review the literature and investigate key factors affecting the lack of improvement in nutrient levels in waterways in urban and agricultural regions. From 94 studies identified in the academic literature, we found that, although 60% of studies found improvements in water quality after implementation of Best Management Practices (BMPs) within the watershed, these studies were mostly modeling studies rather than field monitoring studies. For studies that were unable to find improvements in water quality after the implementation of BMPs, the lack of improvement was attributed to lack of knowledge about BMP functioning, lag times, nonoptimal placement and distribution of BMPs in the watershed, postimplementation BMP failure, and socio-political and economic challenges. We refer to these limiting factors as known unknowns. We also acknowledge the existence of unknown unknowns that hinder further improvement in BMP effectiveness and suggest that machine learning, approaches from the field of business and operations management, and long-term convergent studies could be used to resolve these unknown unknowns.

Integrated assessment modeling reveals near-channel management as cost-effective to improve water quality in agricultural watersheds

“…Second, key pollutants (nitrogen, phosphorus, and sediment) have spatially distinct sources from one another and are mobilized by different mechanisms. Conservation strategies that target single contaminants may not be effective for or may even augment delivery of other contaminants (16,17). Third, the extent of artificial drainage has continued to increase, leading to more rapid movement of water into and through drainage networks, increasing field nutrient losses and riverbank erosion (4,7,18).…”

A Bayesian approach to understanding the key factors influencing temporal variability in stream water quality – a case study in the Great Barrier Reef catchments

“…sugarcane) from perched groundwater should be targeted in these catchments (Melland et al, 2012). Management practices, such as conservation tillage, and adaptation of the 4R concept (right source, right rate, right time and right place) for fertiliser application may help to minimise dissolved nitrogen losses (Lintern et al, 2020;Snyder, 2017).…”

Hydrochemical Indicators Dynamic in Surface Water

“…Soluble oxygen is also necessary for the processes of self-purification of reservoirs, as it participates in redox reactions of organic and mineral substances. The decrease in the concentration of soluble oxygen indicates a change in hydrobiological, hydrochemical processes, the pollution of the reservoir, primarily organic matter [Stephenson and Shabman, 2017; Lintern et al, 2020;Kovacs and Zavadsky, 2021]. The supply of oxygen to the reservoir occurs through the processes of adsorption, photosynthesis, as well as rainwater, and meltwater.…”