Maryland retrofit project reuses storm water for irrigation at elementary school
The Conowingo Elementary School storm water retrofit project was initiated to fulfill requirements of Cecil County, Md.’s Watershed Implementation Plan (WIP) and the proposed Phase II municipal separate storm sewer systems (MS4) permit. The WIP and MS4 both require the restoration and treatment of impervious areas to address the Chesapeake Bay total maximum daily load.
On June 16, 2014, the Chesapeake Bay Trust awarded the Cecil County Department of Public Works Development Services Div. a $244,000 grant to retrofit the school’s campus with storm water management features.
The project had two objectives: First, develop a campus-wide storm water management strategy where one did not previously exist; and second, provide educational resources and platforms to be used to meet state requirements for environmental literacy and green school certification.
The agreement imposed an aggressive schedule integrated with the school calendar to avoid conflicts with student activities. Cecil County awarded the design contract to URS (now AECOM) through a competitive bid process. They were able to collaborate and leverage other funds from Williams Transco to support the project.
During the project’s design, Cecil County’s Development Services Div. and its design consultant, Andy Wishart from URS Inc. (currently with Chesapeake Environmental Consultants) consulted with Perry Willis, executive director for support services for Cecil County Public Schools, and Conowingo Elementary School staff to make sure the county’s plans would not conflict with future school expansion or areas used by school staff.
School staff embraced the idea of integrating storm water management into the landscape, not only to beautify the school grounds, but also to teach environmental concepts. The design team took advantage of the school’s support to design a range of best management practices.
During the design process, a number of existing problems were revealed, including drainage issues, broken and settled concrete outside the school’s library, and a need for an additional play area and irrigation for a butterfly garden. To address these problems, the plans were modified to integrate porous pavement into play areas, create an outdoor classroom and install a rainwater harvesting system.
The rainwater harvesting system designed by Geosyntec Consultants included a 2,500-gal cistern, electronically actuated drain and irrigation valves, and sensors to enable monitoring of system components. The system also offers the ability to monitor the water level in the cistern, soil moisture in an adjacent mulched flower bed, water level within a bioretention cell and precipitation. All components are connected to an intelligent real-time monitoring and control platform provided by OptiRTC. The monitoring and control platform, accessible anywhere with an internet connection, enables real-time visualization of data.
The system allows teachers to remotely release water from the cistern for irrigation and to educate students about the importance of water resources. The system also can continuously monitor weather forecasts and make intelligent decisions. For example, it can release stored water prior to an expected rain event to maximize available storage in the tank. This operation sequence minimizes the occurrence of wet-weather overflows while providing additional benefits, such as water conservation.
Members of the project team, including David Roman of Geosyntec Consultants and Scott Simpson of Opti, found the overall experience to be rewarding. The school and the Cecil County Department of Public Works have been dedicated to providing interactive and educational tools for students to learn about technology, the environment and water resources. They hope the rainwater harvesting system and other green infrastructure components installed on the school grounds are used as inspiration for others seeking ways to educate students in technology and water resources.
Swan Creek Landscaping installed Techo-Bloc pervious pavers, rain gardens, log benches and landscaping to transform the cracked and sunken sidewalk outside the library into a 2,500-sq-ft outdoor classroom.
“The best thing about this project [is that] every single item that was used here for this project, from the stone by the downspouts, the boulders, the stone that is underneath the permeable patio, the brick pavers and all the plants, were all purchased from local Cecil County businesses,” said Trey Giraldi, owner of Swan Creek Landscaping.
The project is estimated to annually reduce nitrogen, phosphorus and sediment by 32.8 lb, 3.5 lb and 0.9 tons, respectively, and it generated a 4-acre impervious area credit by treating the site’s drainage area at a Pe>1. The cost of restoration was $68,750 per impervious acre treated.
The Cecil County Department of Public Works leveraged relatively small matching funds ($31,000) to provide more than just storm water management. The county used this project and its environmental site design practices to engage teachers, contractors, more than 470 students, and the community in a cost-effective manner. The project helped solve drainage issues on the school campus, improved water quality within the local watershed, and helped educate future generations of students about how their actions can help achieve a cleaner and healthier Chesapeake Bay.
“I think that the ecological project that was done at Conowingo Elementary is not only aesthetically pleasing, which builds pride in our school for the children, staff and families, but it has also been a great learning experience for our students,” said Dawn Reed, school counselor for Conowingo Elementary School. “I see individual students and classes exploring the butterfly garden and wetlands often. I see the glow on the students’ faces when they get to have lessons in the outside reading area near our library. I have observed the students that were excited to measure the runoff from the two different roof surfaces of our shed. I myself was very interested when I was told about the cistern and how it is regulated by the weather forecast and technology. This has been a great learning experience for young and old alike.”
Storm water management features, such as a rainwater harvesting system, help teach students about water conservation.