Grantee Research Project Results

Final Report: Solving a Hidden Problem: Rainwater Catchment to Offset Groundwater Depletion

EPA Grant Number: SU833939
Title: Solving a Hidden Problem: Rainwater Catchment to Offset Groundwater Depletion
Investigators: Bank, Larry , Potter, Kenneth W.
Institution: University of Wisconsin - Madison
EPA Project Officer: Page, Angela
Phase: I
Project Period: April 21, 2009 through April 21, 2011
Project Amount: $10,000
RFA: P3 Awards: A National Student Design Competition for Sustainability Focusing on People, Prosperity and the Planet (2008) RFA Text | Recipients Lists
Research Category: Pollution Prevention/Sustainable Development , P3 Awards , P3 Challenge Area - Safe and Sustainable Water Resources , Sustainable and Healthy Communities

Objective:

These students contributed to this project: Bachrach, Andrea - UW-Department of Biological Aspects of Conservation; Bianco, Stephanie - UW-Department of Civil and Environmental Engineering; Bradford, Anna - UW-Department of Civil and Environmental Engineering; Jones, Parker - UW-Department of Landscape Architecture; Kenney, John - UW-Department of Mechanical Engineering; Santarius, Kate - UW-Department of Civil and Environmental Engineering; Utschig-Samuels, Stephen - UW-Department of Chemistry; Zeise, Lea - UW-Department of Mechanical Engineering; Zimmerman, Brian - UW-Department of Civil and Environmental Engineering

Through our research, we hope to bring the often overlooked issue of groundwater depletion to light in order to gain the public attention it deserves, and to encourage people to actively seek out sustainable solutions to this serious problem. Aquifers worldwide are being depleted at much greater rates then they are being replenished. The use of groundwater for irrigation greatly contributes to the exhaustion of this precious resource. Impervious surfaces such as roofs, streets and parking lots also contribute to the depletion of groundwater. These surfaces cause large amounts of runoff, which flows into rivers and lakes and is not allowed to replenish the groundwater. Furthermore, the nutrients this runoff water collects leads to the eutrophication of lakes and streams, which threatens aquatic life. Continued trends of unsustainable infrastructure design and inefficient irrigation methods will severely limit access to clean water and will destroy the beautiful habitats that are not only home to millions of plants and animals, but are also an important part of our livelihood, identity, and community.

Our research focuses on finding widely applicable solutions to this pressing issue. The collection of storm water runoff is an underutilized, but highly effective method of offsetting groundwater depletion. Water can be stored and dispersed as needed for irrigation by diverting storm water runoff into cisterns. Both phases of our project are a direct application of this solution. Not only will utilizing stored rainwater for irrigation offset the use of municipal groundwater, it will also increase the amount of water reintroduced into the groundwater supply instead of the rainwater becoming runoff. The city of Madison alone uses 1.19 million gallons of water per day for irrigation purposes during the watering season, so rainwater catchment systems have the potential to make a huge positive impact on the future availability of clean water as well as the health of aquatic ecosystems in the Madison area.

Phase I is a pilot project designed to re-route storm water runoff into cisterns to be used to irrigate a small garden at the Wisconsin Institute for Medical Research (WIMR). Using soil saturation sensors in conjunction with the irrigation system will allow us to ensure that the system only provides water only when the soil saturation is below a certain level. The same sensor systems will be incorporated into the second phase of the project. The soil sensors will be hooked up to a data logger which will track data periodically. We will use this data to create hydrological models using a modeling program called RECARGA. The true capabilities of these rainwater catchment systems will be tested to determine the recharge rate of groundwater sources. If we receive additional funding, we will use the models created and the data collected from our pilot project to design a 15,000 gallon cistern to also be installed on the WIMR building. With the implementation of this large cistern to this complex, we will be furthering the advancement of sustainable building practices as well as reducing runoff and depletion of Madison’s groundwater.

The data collected from the second phase of our project will allow us to perform a cost-benefit analysis of using large scale water catchment systems to irrigate urban landscapes and gardens in order to offset groundwater use and reduce runoff. As with our pilot project, the goal is to maximize output, which is groundwater recharge, while maintaining the health of the irrigated vegetation and while minimizing costs. Ultimately, all of the rain water collected in our cistern will be reintroduced into the aquifer, so the amount of water collected in our cistern can be translated directly into how much water percolates into the water table. We will also use our research to educate the community on the issue of groundwater depletion, and more importantly, how to incorporate rainwater catchment systems into several different infrastructure designs to make them more sustainable.

Summary/Accomplishments (Outputs/Outcomes):

The knowledge our team gained through work on our Phase I project came from research and also from experiences with the university's approval process. While doing laboratory research we learned a number of key things. Setting up a smallscale cistern and pump system allowed us to test our irrigation system and familiarize ourselves with its components. We set up plots with two different types of soil to be irrigated by this pumping system, and installed soil moisture sensors and a data logger to track data. We tested on different soil types to account for different infiltration rates. This allowed us to confirm that the system would deliver an appropriate amount of water to keep each of the soils at a desired moisture level. This proved useful in showing that each individual component of the irrigation system works together, which will be essential when installing the Phase I cisterns. Through other experiments, we determined that the flow valves require high water pressure in order to be actuated by the control unit. Therefore, the pump we use in the cisterns will need to provide an adequate amount of water pressure. Ideally, soil will be kept at maximum saturation, allowing for the plants to be well fed, and the aquifer to be replenished at the highest possible rate. This condition will be achieved through the use of the soil saturation sensors. Overall, the laboratory research has provided us with a knowledge base to draw from when installing the Phase I cistern, as well as confidence in the system we are going to use.

Through the first phase of our project, the team learned a lot about the UW's approval process for installations on campus buildings. Acquiring permission to install the cistern took longer than initially expected. Our project was officially approved on October 28th, 2008, and due to the harsh climate of Wisconsin, the two 305 gallon cisterns will not be implemented until April 15th, 2009. Although this has limited our measurable results for the Phase I project, the experience we gained will be essential to designing and gaining approval for the 15,000 gallon Phase II cistern. We have built a network of contacts within the University and throughout the surrounding community, and these partnerships will be crucial to the success of future projects.

Conclusions:

Using stored rain water for irrigation is an effective way to offset the use of groundwater and reduce runoff, which has important implications for people, our prosperity, and the planet. Implementing rain cisterns is a solution to two major issues with water management: the excessive pumping of groundwater for irrigation purposes, and the runoff that results from unsustainable building design. Furthermore, when catchment systems are used in conjunction with soil saturation sensors, there are additional water and cost savings as opposed to using traditional timed irrigation systems. Catchment systems can be as sophisticated or as simple as you like, from basic rain barrels to systems like ours. No matter how simple or complex the system, it is an effective solution to an understated, yet pressing issue.

Proposed Phase II Objectives and Strategies: One objective of the second phase of our project is to design and implement a 15,000 gallon cistern on the WIMR building, which will collect runoff from the roof to be used for the irrigation of the surrounding landscape. This will be the largest project of its kind in Dane County, and its success will require the dedication and support of several professionals. Our team will be working with the UW-School of Medicine and Public Health, whose faculty will provide the means to build the large cistern. We will also be working with Boldt Construction Company. They will help us design the cistern, and will manage and install the system.

We will use the data collected from the Phase II cistern as well as the pilot cisterns to create hydrological models of the irrigated area. Using these models, we will be able to effectively determine other areas on campus that would be compatible with rainwater catchment systems. We will work with the UW-Facilities and Planning Management Department to start establishing a campus wide network of cisterns to collect and distribute rainwater across campus.

The main objective of our project is to instill a spirit of conservation and land stewardship amongst UW students, faculty and all other community members. We will strive to raise awareness of the serious consequences of groundwater depletion. We hope to demonstrate that these types of projects are possible in nearly every situation, from home use to large scale industrial or agricultural applications. We will accomplish this through a comprehensive outreach program to our campus, other state schools, and the rest of the community.

Journal Articles:

No journal articles submitted with this report: View all 4 publications for this project

Supplemental Keywords:

irrigation, cistern, rainwater, rainwater catchment, groundwater, aquifer, groundwater depletion, water conservation, sustainable water management, soil moisture, groundwater recharge, rain garden, hydrological model, impervious surfaces, unsustainable infrastructure design, runoff

Relevant Websites:

http://www.wbcsd.org/DocRoot/1akheXxfOpeGtgrJS8sI/Water_facts_and_trends.pdf
http://pubs.usgs.gov/fs/fs-103-03/
http://www.groundwater.org
http://www.wnrmag.com/supps/2006/apr06/intro.htm
http://co.water.usgs.gov/nawqa/hpgw/factsheets/DENNEHYFS1.html
http://www.sciam.com/article.cfm?id=facing-the-freshwater-crisis&page=5

Progress and Final Reports:

Original Abstract

2009

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The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.