Spatial Analysis of La Nana Bayou Watershed to Assess Stream Health

<p>The purpose of this study was to evaluate the feasibility of using land cover mapping to identify water quality indicators within a river basin, assessing whether this method provides greater efficiency compared to traditional field-based water quality testing. Land cover mapping has efficiently monitored environmental changes by detecting alterations within specific areas. With the La Nana Bayou Watershed positioned in the heart of Nacogdoches City, an urbanized environment; it is subject to human induced alterations that can negatively affect the natural functionality of its system. When water quality indicators are successfully related to land cover maps, changes within the landscape that directly impact a watershed’s health can be monitored routinely with ease. Over a 20-year span within the study area, the following land cover types were used as water quality indicator, including riparian zone, impervious cover, and forest cover. The indicators associated with the La Nana Bayou Watershed was studied using land cover maps attained from the National Land Cover Databases (NLCD) for the years 2001, 2006, 2011, 2016, and 2021. The assessment of water quality based on land cover maps was validated for accuracy using field measured water quality parameters and census data. Throughout the 20-year time span studied, the La Nana Bayou Watershed had many water quality indicators that could be monitored over time using land cover change analysis. The analysis completed within and outside the simulated riparian zones was used to confirm that the watershed underwent positive and negative changes affecting the watershed natural functionality. The positive influence was highlighted through the increases of forested land cover, while the constant implication of newly developed land cover within the watershed’s boundary continued to pose negative impact on the aquatic health of the watershed. These findings were not only determined using land cover change analysis but through the validation process using census and water quality parameters associated with the watershed. The results indicated that the areas with the most urbanized cover had the most degraded water quality. Through this validation, it was determined that land cover mapping is a useful approach that can be utilized to monitor water quality changes of lentic systems overtime.</p>

Name thesis:degree_name

Master of Science - Environmental Sciences

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Environmental Science

Year dc:date.available

2025

Author dc:creator

• Gabbert, Rylee G

Contributors dc:contributor

• I-Kuai Hung
• Daniel Unger
• Jiyeon Kim

• Environmental Science
• Spatial Science
• GIS
• Landcover Mapping
• Environmental Sciences

Repository record dc:identifier

https://scholarworks.sfasu.edu/etds/656

OAI identifier oai:identifier

oai:scholarworks.sfasu.edu:etds-1668