Date of Award

Fall 12-11-2020

Degree Type


Degree Name

Master of Science - Environmental Sciences


Environmental Science

First Advisor

Dr. Matthew McBroom

Second Advisor

Dr. Kenneth Farrish

Third Advisor

Dr. Yanli Zhang


Nine experimental metal roofs with rainwater harvesting systems were constructed and water quality parameters were measured in 2016-2017 in order to evaluate the effects of arboreal overhang on roof-harvested rainwater quality collected in East Texas. Three treatments were evaluated: Rainwater collected from roofs without any overhanging tree vegetation, rainwater collected from roofs under predominantly Southern yellow pine tree cover, and rainwater collected from roofs under predominantly hardwood tree cover. Rainwater was collected from these roofs for one year. The effects of canopy cover on water quality parameters, comparison to drinking water standards, first-flush efficiency, and seasonal effects were evaluated.

Significant differences among water quality parameters were observed among cover types for all analyzed parameters except nitrate-N and nitrite-N, which were often below the method detection limit. Drinking water standards were exceeded in the ambient rainfall as well as the tank samples from open, pine canopy, and hardwood canopy covered roofs for pH, color, turbidity, total coliforms and E. coli. Both nitrate-N and nitrite-N were within drinking water standards from all sources throughout the study. Use of first-flush diverters resulted in improved water quality of sampled water in 67% of comparisons. The bacterial standards were still exceeded even after first-flush diversion indicating the necessity for disinfection before roof-harvested rainwater could be potable. Seasonal differences in the analyzed parameters were observed for seven of eight parameters in the pine roof-harvested rainwater, five out of eight for the hardwood roof-harvested rainwater, and in only one of the direct roof-harvested rainwater. Quantifying the effects of tree cover on roof-harvested rainwater contributes to the improvement of the designs of rainwater harvesting filtration and disinfection systems, making this practice an even more viable alternative for meeting household water demands.

Creative Commons License

Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.



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