Date of Award
8-2026
Degree Type
Thesis
Degree Name
Master of Science - Forestry
Department
Forestry
First Advisor
Matthew McBroom, Ph.D.
Second Advisor
Jeremy Stovall, Ph.D.
Third Advisor
Yanli Zhang, Ph.D.
Fourth Advisor
Yuhui Weng, Ph.D.
Fifth Advisor
Daniel Colopietro, Ph.D.
Abstract
Developing cities and increased impervious surfaces has resulted in more surface runoff and severe flooding. Harris County, Texas has experienced major flooding events, such as Hurricane Harvey in 2017 which was estimated to be a 9,000-year flood event. The Harris County Flood Control District (HCFCD) is dedicated to creating, maintaining, and finding new ways to reduce flooding damage such as the use of detention basins as green infrastructure. These basins are either populated by grass or are planted with various tree species. This study will identify the planted trees’ canopy interception loss, reference evapotranspiration, and enhanced soil infiltration effects within the HCFCD’s basins to further understand and quantify the influence these trees have on flood mitigation.
Canopy interception loss was calculated by measuring both drop count (a consistent and known size measured in the weather station) and precipitation on a non-forested basin and under the canopy of a forested basin. A negative binomial mixed model and Tweedie mixed model were used to compare drop count and precipitation data. Reference evapotranspiration (ETo) was calculated using the FAO Penman-Monteith equation for a non-forested and forested basin and further analyzed using an analysis of variance (ANOVA) and Tukey’s honestly significant difference test. Soil infiltration was measured across 16 sites and analyzed using a hurdle model with a Fisher’s exact test and nested ANOVA. Soil Moisture release curves were developed at both the forested and non-forested site. These curves were then compared for soil structure and behavior analysis.
The forested canopy was calculated to have intercepted 11,684 drops and 181.36 millimeters of precipitation over the study period. Drop counts were significantly different between cover types (Pr(>|z|) = 1.5E-08), as was precipitation (Pr(>|z|) = < 2E-16). These results suggest that drop count accumulation every 15 minutes in the non-forested basin was 66% higher than the forested basin, and precipitation accumulation was 49% higher, supporting the hypothesis that the canopy intercepted a significant amount of rainfall. Reference evapotranspiration models were compared between the non-forested basin and the forested basin. Reference evapotranspiration at 2 meters for the non-forested basin was significantly higher than the forested basin, although ETo in the forested basin only identified understory rates. Analysis of month types also suggests that ETo rates follow a clear seasonal pattern. Saturated areas were included in the Fisher’s exact test, which found that there was a significantly higher (p = 0.04413) chance of having saturated areas in non-forested basins than forested basins by 8.14 times. There was, however, no significant (Pr(>F) = 0.71) difference between the infiltration between cover types and no significant (Pr(>F) = 0.16) difference between the infiltration of sites nested in cover type. Soil moisture release curves illustrated the well distributed pore size of forested soils and a very uniform distributed pore size of non-forested soils, suggesting there is more plant available water in the forested soils.
Repository Citation
Perez, Alexandria N. C., "Forest Cover Effects on Canopy Interception Loss, Evapotranspiration, and Soil Infiltration on Stormwater Detention Basins" (2026). Electronic Theses and Dissertations. 671.
https://scholarworks.sfasu.edu/etds/671
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