Document Type

Thesis - Open Access

Award Date

2024

Degree Name

Master of Science (MS)

Department / School

Agricultural and Biosystems Engineering

First Advisor

John McMaine

Abstract

Several factors such as global climate change, population growth, urban and agricultural expansion, rising water demand, unequal water distribution, hydro-political conditions, declining water quality, rainwater scarcity, and temperature-induced drought contribute to water resource degradation. Rainwater harvesting (RWH) emerges as a sustainable solution, involving the collection and storage of rainwater for agriculture, livestock, and domestic use. RWH reduces reliance on municipal water, mitigates climate change impacts, and decreases runoff. Conventional RWH systems in the US vary in effectiveness. Increasing storage and water use enhances RWH effectiveness, improving stormwater runoff and reducing potable water use. High tunnel production of vegetable crops has a strong potential for use of RWH for both reduction in potable water use for irrigation and reduction in stormwater runoff, generated by the high tunnel roof’s impervious surface. A high tunnel is an unheated greenhouse. The roof provides the source of runoff to fill the RWH tank and irrigation water for vegetable production inside the high tunnel. While RWH would be complementary with high tunnel vegetable production, there has been little research into the potential performance for irrigation replacement, runoff reduction, and cost-effectiveness. This study evaluated a high tunnel roof with an RWH system in 12 states for growing tomatoes, cucumbers, and beets, focusing on irrigation, runoff reduction, and cost analysis. Irrigation replacement, varying by state and tank size, shows that in CA, RWH can meet about 3% and 17% of irrigation needs for 250-gallon and 3000-gallon tanks, respectively, while in VT, it can reach 39% and 99%, respectively, with the highest IR (%). The optimal size for irrigation replacement is generally 1,500 gallons. Rainwater harvesting effectiveness depends on tank size, rainfall, and crop types. States with lower rainfall during the growing season have higher percentages of runoff reduction. Rainwater harvesting for tomatoes is more cost-effective than for cucumbers and beets due to higher water use and a longer growing season. Runoff reduction is limited in most states, with CO having the highest flow reduction of 80%. The economic benefits of rainwater harvesting depend on factors like local water prices, rainfall, and harvested rainwater amount. The most cost-effective scenarios include VT with the highest gain ($307) for a 1000-gallon tank, followed by KY ($1500) for a 260-gallon tank, and GA ($144) for a 1000-gallon tank. RWH is most cost-effective in regions with high rainfall during the growing season and expensive main water. While RWH may not be exceptionally economically advantageous for all regions, it can still provide benefits of runoff reduction, promoting cost savings and efficient use of potable water resources.

Library of Congress Subject Headings

Water harvesting -- United States.
Rainwater -- United States.
Greenhouses -- United States.
Vegetables -- Harvesting -- United States.

Publisher

South Dakota State University

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Rights Statement

In Copyright