Tailored Watershed Assessment and Integrated Management (TWAIM): A Systems Thinking Approach

Abstract

Control of non-point source (NPS) water pollution remains elusive in the United States (US). Many US water-bodies which have been primarily impacted by NPS pollution have not achieved water quality goals set by Clean Water Act. Technological advances have been made since 1972, yet many water resources fail to meet water quality standards. Common Pool Resources Theory is considered to understand the human dimension of NPS pollution by exploring anthropogenic activities superimposed upon dynamic ecosystems. In the final analysis, priority management zones (PMZs) for best management practice (BMP) implementation must have buy-in from land managers. TWAIM is an iterative systems thinking approach to planning, collecting landscape and land use information and communicating systems understanding to stakeholders. Hydrologic pathways that link the physical, chemical and biological characteristics influence processes occurring in a watershed which drive stream health and ecological function. With better systems understanding and application by technical specialists, there is potential for improved stakeholder interaction and dialogue which could then enable better land use decisions. Issues of pollutant origin, transport, storage and hydraulic residence must be defined and communicated effectively to land managers within a watershed context to observe trends in water quality change. The TWAIM concept provides a logical framework for locally-led assessment and a means to communicate ecohydrologic systems understanding over time to the key land managers such that PMZs can be defined for BMP implementation. OPEN ACCESSWater 2011, 3 591

Combining Tools from Edge-of-Field to In-Stream to Attenuate Reactive Nitrogen along Small Agricultural Waterways

“…N attenuation mechanisms that may be boosted include physical retention, microbially mediated transformation to gases, and biological retention from assimilation, uptake, or immobilization. Tool stacking [16,18,19] should support functioning of multiple N attenuation mechanisms across locations and scales (Table 2). Moreover, implementing in-field, edge-of-field, and in-stream attenuation tools in a targeted and stacked way, focusing on small stream networks, may also provide the most cost-effective reduction of nutrient export from agricultural land to large river networks [12,116,117].…”

“…Our definition of small waterways encompasses ephemerally or intermittently flowing channels to permanently inundated second-order ditches and streams that are more likely to intercept local rather than regional groundwater [17]. The RPRP framework enables conservation planners to identify locations where tool stacking or 'treatment trains' consisting of multiple tools [16,18,19] can be implemented along the various flow pathways in a catchment to maximize water quality improvements. In practice, however, the links between field-scale variability in N export (i.e., hydrological delivery pathways and timing) and N attenuation at the catchment scale are difficult to establish.…”

Using social criteria to select watersheds for non-point source agricultural pollution abatement projects

“…In response to these failures, a number of agencies and organizations have initiated intensive, targeted outreach approaches at the watershed (HUC 10) and sub-watershed (HUC 12) levels (Tomer, 2010;Magner, 2011;Nowak, 2012;Legge et al, 2013;Tomer et al, 2013). These approaches incorporate emergent planning tools such as LIDAR imaging and novel management technologies such as tile drainage treatment wetlands, bioreactors and two-stage ditches.…”

Right practice, right place: A conservation planning toolbox for meeting water quality goals in the Corn Belt

“…Research suggests that the HUC-12 scale is typical of the scale of rural social networks (Babin et al 2016). When landowners and operators know each other as neighbors, support for collective action to address water quality problems can become an issue of community pride (Magner 2011). An additional reason for preferring the HUC-12 scale is that headwater streams (which form a very large proportion of the stream network in larger watersheds) are extremely effective at removing N (Peterson et al 2001); by working at the HUC-12 scale, it is possible to identify opportunities to enhance nutrient removal in the channels and riparian zones of these streams.…”

“…Table 1 enables conservation planners to identify where BMP "stacking" or a "treatment train" (Magner 2011;Lien and Magner 2017) of practices can be implemented in series along flow paths from ridgetop to waterbody to maximize water quality improvement. We have integrated the information on agro-hydrologic land-…”