Modelling the feasibility and cost-effectiveness of edge-of-field mitigations for reducing nitrogen and phosphorus loads in the Waituna Lagoon Catchment, Southland

Evaluating the Cost-Effectiveness of Green Infrastructure for Mitigating Diffuse Agricultural Contaminant Losses

“…Another limitation is that we assume the sub-catchment either has a single land manager or that managers are able to take communal action to enact the most cost-effective combination of systems. The potential for collective responses to diffuse pollution mitigation, as evidenced in the Waituna catchment study by Weeber et al [12], suggests a re-evaluation of traditional individual farm-based approaches. Collective strategies across catchments could offer cost efficiencies but also introduce complexities for equitable implementation across diverse agricultural landscapes.…”

“…Other studies have compared a subset of mitigation systems for a specific catchment. For example, Weeber et al [12] assessed the feasibility and cost-effectiveness of implementing CW, WB, and aluminized zeolite filters in the Waituna catchment. Tanner et al [7] provided a semi-quantitative framework for selecting interceptive mitigation systems for different hydrological landscape types.…”

Implementing constructed wetlands for nutrient reduction at watershed scale: Opportunity to link models and real-world execution

“…Much of the research on the design and performance of constructed wetlands has been conducted at the unit-level, where one wetland or a series of cells comprising a wetland treatment system is evaluated by in-out type measurement and modeling (USEPA 2000; Kadlec and Wallace 2008). In the context of treating excess nutrients from nonpoint agricultural sources specifically, unit-level constructed wetlands treating small farming catchments are often studied as an edge-of-field nutrient reduction practice for farm runoff (Williams et al 2016;Mendes 2020Mendes , 2021Gordon et al 2021a;Soldo et al 2022;Weeber et al 2022;Mitchell et al 2022). Farmers can apply for financial and technical assistance from the USDA National Resources Conservation Service (NRCS) for adding a constructed wetland for nutrient runoff reduction as an approved practice under different programs like the Environmental Quality Incentives Program (EQIP) (USDA NRCS 2023).…”

“…The Soil Water Assessment Tool (SWAT) is a popular model used for characterizing the potential effectiveness of constructing wetlands in watersheds (Krysanova and White 2015;Ikenberry et al 2017;CARD 2019). SWAT is sometimes paired with other tools and/or an optimization algorithm to assess the cost-effectiveness of wetlands in achiev-ing nutrient reduction targets set by TMDLs or similar regulations (Gordon et al 2021a;Weeber et al 2022;Yang and Best 2015;Amin et al 2020;Heiskary and Markus 2001;Preston et al 2011;Iavorivska et al 2021;Singh et al 2019). Cost-effectiveness, in this context, is a relative term indicative of the cost per unit of treatment.…”