**2. Study Area**

The Laguna Madre is composed of two sections: The Upper Laguna Madre and the Lower Laguna Madre (LLM). The Laguna Madre is also unusual for being one of only five hypersaline coastal ecosystems in the world [31,32]. This estuary encompasses 20% of Texas's protected coastal waters while contributing 40–51% of the state's commercial fish catch historically as well as providing a common ground for migratory birds [1,32,33]. The LLM is the area of interest in this study since the north and central watersheds inflow to two of the three segments that are currently considered impaired. The north and central watersheds encompass an area of 3116 km<sup>2</sup> located in South Texas in the northern and central area of the LRGV region. The LRGV is a semiarid region in South Texas bordered by Mexico to the south and the Gulf of Mexico to the east [16]. This watershed is comprised of three main waterways: HWMD in the southwest extending to the east, RVD in the north, and IBWCNF in the southeast (Figure 1). The study area takes up a large plain of South Laguna Madre Watershed Hydrologic Unit Code 12110208 (8-digit HUC). North and central watersheds encompass 37% of the area in the LLM watershed. The study area has significant hydrology challenges due to flat terrain, where previous studies will be considered when processing the data. Its elevation gradually slopes from 102 to 0 m with a high range of precipitation between 50–70 cm/year. The Arroyo Colorado is located south of the IBWCNF waterway. Although relatively close to one another, they are not considered intersecting. In general, soils in the LRGV region consist of calcareous to neutral clays, clay loams, and sandy loams [20]. Therefore, the low permeability of the soils influences the drainage characteristics. *Sustainability* **2021**, *13*, x FOR PEER REVIEW 5 of 23

**Figure 1.** Location and elevation map of Study area is the North and Central watersheds located in the Lower Rio Grande Valley, of South Texas, Hidalgo/Willacy Main Drain (HWMD), Raymondville Drain (RVD), and International Boundary & Water Commission North Floodway (IBWCNF). **Figure 1.** Location and elevation map of Study area is the North and Central watersheds located in the Lower Rio Grande Valley, of South Texas, Hidalgo/Willacy Main Drain (HWMD), Raymondville Drain (RVD), and International Boundary & Water Commission North Floodway (IBWCNF).

The methodology to collect and analyze data for the characterization of the three wa-

In this study, cyberinfrastructure was established by developing the River and Estuary Observatory Network (REON) (http://dev.reon.cc:8607/, 17 August 2021). REON provides an extensive overview of all the available data from national, state, and local sources on this site. This platform helped in obtaining quality data for an overview of the north and central watersheds' characteristics, where stakeholders from the study area could support the characterization. The website now serves as a cyber-collaboratory platform for engaging stakeholders with an interest in data and information for a certain location [6]. Due to the wide inventory of data, the cyberinfrastructure also supported the acquisition of geospatial data, making the process more efficient which consisted of having all the geospatial data in only one source, REON. The value of the REON website in this

were obtained to develop a GIS database through a cyberinfrastructure to recognize the dominated attributes contributing to the watersheds. Therefore, the elaboration of watershed maps facilitated the identification of these attributes. Due to the wide inventory of data, a cyberinfrastructure was used to make data collection more efficient. Then, the elevation data were reconditioned to better represent the drainage areas of the watershed with respect to the terrain of the study area. In addition, NPS and PS pollution data were obtained to fully characterize the watersheds and to determine relative sources of pollution. Non-geospatial data were divided into two sections: water quality and flow data. Water quality was incorporated to determine the relationships between potential sources of pollution with the parameters found in each watershed. Available flow data were used

to determine the load concentrations for each water quality parameter.

**3. Methodology** 

*3.1. Cyberinfrastructure Development* 
