The University of New Hampshire has become increasingly concerned with storm water management on the Durham campus. Due to Federal regulations many regional municipalities are feeling pressure to enhance and increase management of storm water to reduce impacts to surface waters. The specific objective of this proposal is to demonstrate reductions in the discharge of storm water runoff from UNH-Durham campus properties. The construction and use of three Low Impact Development (LID) integrated management systems on UNH property will help UNH and the UNH Stormwater Center to champion innovative approaches in the state and region for reducing storm water runoff and improving the health of coastal watershed areas

Houle, James

Jones, Stephen H.

English

UNH Scholars' Repository

University of New HampshireUniversity of New Hampshire Scholars'RepositoryPREP Reports & Publications Institute for the Study of Earth, Oceans, and Space(EOS)9-29-2006Low Impact Storm Water Management Projects atthe University of New HampshireStephen H. JonesUniversity of New Hampshire - Main Campus, Stephen.Jones@unh.eduJames HouleSky Juice New EnglandFollow this and additional works at: https://scholars.unh.edu/prepPart of the Marine Biology CommonsThis Report is brought to you for free and open access by the Institute for the Study of Earth, Oceans, and Space (EOS) at University of NewHampshire Scholars' Repository. It has been accepted for inclusion in PREP Reports & Publications by an authorized administrator of University ofNew Hampshire Scholars' Repository. For more information, please contact nicole.hentz@unh.edu.Recommended CitationJones, Stephen H. and Houle, James, "Low Impact Storm Water Management Projects at the University of New Hampshire" (2006).PREP Reports & Publications. 275.https://scholars.unh.edu/prep/275Low Impact Storm Water Management Projects at the University of New Hampshire  A Final Report to the New Hampshire Estuaries Project  Submitted by  Project PI & Co-Manager:  Dr. Steve Jones Associate Research Professor University of New Hampshire Jackson Estuarine Laboratory Adams Point Durham, NH 03824 (603) 862-2705  Co-Manager:  Mr. James Houle SkyJuice New England 1015 1st Crown Point Road Strafford, NH 03884 (603) 330-312   September 29, 2006   This report was funded in part by a grant from the New Hampshire Estuaries Project, as authorized by the U.S. Environmental Protection Agency’s National Estuary Program.   2TABLE OF CONTENTS  I. Project Summary        3 II. Project Description       3 III. Project Site Selection       3 a. UNH Stormwater Center      4 b. UNH Jackson Estuarine Laboratory      4 IV. Project Outcomes        5 a. Rainwater storage:  UNH Stormwater Center and UNH JEL 5 b. Tree filter bioretention cell:  UNH JEL    5  c. Self-guided descriptions of innovative storm water  management BMP’s       6 d.   Outreach and education program     6  V. Estimation of Runoff Volume and Pollutant Load Reduction  6 a. Volume reduction       7 b. Pollutant load reduction       7 VI. Conclusions        8 VII. References        8  APPENDIX A         9         3I.  Project Summary    The University of New Hampshire has become increasingly concerned with storm water management on the Durham campus.  Due to Federal regulations many regional municipalities are feeling pressure to enhance and increase management of storm water to reduce impacts to surface waters. The specific objective of this proposal is to demonstrate reductions in the discharge of storm water runoff from UNH-Durham campus properties.  The construction and use of three Low Impact Development (LID) integrated management systems on UNH property will help UNH and the UNH Stormwater Center to champion innovative approaches in the state and region for reducing storm water runoff and improving the health of coastal watershed areas.  II.  Project Description    LID is a storm water best management practice (BMP) involving the use of small-scale storm water management controls that are placed at strategic points to control the impacts of contaminants generated from storm water runoff from transportation infrastructure.  These sustainable management measures are designed to filter pollutants, control peak flow rates, and reduce the total volume of rainfall runoff.   The project site was the University of New Hampshire (UNH), located in Durham, New Hampshire.  The primary campus is comprised of 300+ buildings located on 1,100+ acres of predominantly developed land, including impermeable roof and ground surface.  The ongoing concern about managing storm water at UNH was in harmony with a number of NHEP highest priority action items.  The project was an excellent opportunity to demonstrate how to confront coastal storm water problems common to UNH and coastal municipalities by using LID strategies in effective, yet low-cost and easily adoptable ways.  Specific project objectives achieved through this project include the following:  • Construction of demonstration-level BMP’s at two high profile locations on the UNH campus.   • Creation of self-guided descriptions of and outreach material for the three innovative storm water management BMP’s installed.  • Development and initiation of an outreach and education program • Estimations of runoff volume reduction and pollutant load reduction from BMP’s.   III. Project Site Selection  Collaborations between NHEP, the UNH Jackson Estuarine Laboratory, UNH Environmental Hazard and Safety Office (EHS), UNH Facilities, UNH Stormwater Center, and SkyJuice New England all contributed to successful completion of the project.  In order to maximize visibility and outreach impact two high profile locations were chosen.     4a.)  UNH Stormwater Center The UNH Stormwater Center had several areas that could accommodate additional LID systems beyond those involved as pilot systems in experiments.  One area was the on-site building that houses the monitoring equipment for the pilot systems.  The installation of a rainwater runoff cistern and irrigation system would serve to minimize the impact of the roof runoff on nearby systems. In addition, specific attributes of the UNH Stormwater Center made it a compelling location for fulfillment of project objections.  First, it is the University’s storm water research headquarters and was already the site for research on a variety of LID applications.  Second, the center plays host to hundreds of storm water technology end-users through on-going technical workshops.  The backgrounds of workshop participants are wide ranging and include town council, planning and conservation board members, consulting engineers, watershed alliances, state (MA, NH, VT, ME) and federal DOT environmental agencies federal Coastal Training Programs, NEIWPCC, NEWWA, NHWWA, NHEP, MACZM, local municipal officials, town engineers, and other researchers involved or interested in BMP design and stormwater management.  Increasingly organizations such as the New England Water Works Association are choosing to host annual meetings, technical workshops, and conference venues at UNH in order to demonstrate first hand the research products of the center.  These outreach and education efforts are critical to the success of any program.  All of these attributes provided a high exposure venue for introduction, demonstration, and reporting on appropriate source control BMP’s that can be incorporated in storm water management plans.   b.)  UNH Jackson Estuarine Laboratory This UNH Jackson Estuarine Laboratory (JEL) is a prime location for LID demonstrational techniques. Governors, congressmen, researchers, outdoor enthusiasts, educators, school children, researchers and college UNH classes and individual students visit JEL throughout the year, making it a great educational opportunity.  The lab is built at the edge of the Great Bay Estuary.  This critical receiving water would obviously benefit from  integrated LID strategies that intercept and treat storm water runoff from surrounding impervious surfaces.  In addition, the well that serves JEL freshwater needs occasionally is inadequate for meeting demands, and augmentation of freshwater supply would benefit the ongoing research projects at the lab.  The conditions at the Jackson Estuarine Laboratory prior to the project resulted in large volumes of runoff from the parking lot and building surfaces that flowed over small, steep-sloping shoreline areas and unimpeded into the estuary.   The project focused on two of the most critical areas, the parking lot and associated runoff that flowed down the paved walkway stairs, and the roof runoff that fell onto the narrow area of lawn between the lab building and the shoreline riparian zone.  The intent was to construct a LID to intercept runoff from flowing off the parking lot and down the walkway, and to intercept some of the rainfall runoff from the roof on the side facing the water to enable re-use. The two installed project BMPs currently help treat runoff from the 8,750 square feet of impervious roof footage and runoff from the impervious land area covered by the parking lot and access road.  5 IV.  Project Outcomes   a.)  Rainwater storage:  UNH Stormwater Center and UNH JEL   Rain water runoff cisterns are roof water management devices that provide on-site storm water retention capacity.  On-site storage combined with later reuse of storm water provides an opportunity for water conservation with significant reduction of utility costs, and can help to mitigate impacts of runoff in fragile riparian areas.     A 550 gallon cistern was installed at each site location. Each cistern is 48” x 72” HDPE plastic and is green in color to minimize light penetration and limit algae growth.  All system require low maintenance regimes that include annual inspection for leaks and built up sediments and winterization, or emptying prior to freezing conditions.  A. at JEL: 1) gutter serving 400 ft2 of roof; 2) hooked up to cistern via a 20 ft length of downspout with a valved shut off; 3) overflow pipe; 4) a ¾ HP jet pump with pressure tank to supply pressurized output to an adjacent spigot. B. at SC: 1) gutter serving 200 ft2 of roof; 2) hooked up to cistern via a 5 ft length of downspout; 3) overflow pipe; 4) a ¾ HP jet pump with pressure tank to supply pressurized output to an adjacent spigot. C. At SC: 500 ft of drip irrigation tape was installed with a pressure reducer and inline filter to efficiently water existing landscaping at the site.  See appendix A for unit specifications.  The attachment is part of an informational package that is delivered to all visitors of technical demonstration workshops for the UNH SC.  b.)  Tree filter bioretention cell:  UNH JEL A tree filter bioretention cell is a storm water management technology that treats storm water through manufactured soil and conditioned planting of biologic retention materials and landscaping.  The bioretention concept is designed to detain and filter storm water runoff before it is conveyed to local receiving waters.  A tree filter bioretention cell was installed at the UNH JEL to treat runoff from the lab’s parking area.  The system also served to eliminate erosion that had been occurring bordering the walkway and weathering of walkway materials.  The Bioretention Tree Filter Cell is composed of a 6’ diameter 4’ deep concrete catchbasin with an internal 8” by-pass and an 8” underdrain.  The catchbasin is open bottomed to facility infiltration and ground water recharge.  The underdrain and sub-base in bedded in 1’ of ¾” crushed stone and the catchbasin was backfilled with a constructed soil media mix consisting of 80% sand, 10% hardwood chips, and 10% compost.  To develop a vegetative biotic root zone, a native shrub, Viburnum Opulus ‘Roseum’ was planted along with perennial rye grass.  The tree filter was designed to treat a one inch rainfall event (92% recurrence interval) off of 0.14 acres of impervious parking area with a peak flow of 0.1 cfs.  Storms larger than 1 inch will ultimately by-pass however the first 1 inch, or “first flush” of a large rainfall event is still treated.  The system requires low maintenance regimes that include annual inspection for  6vegetation health, evidence of internal and external erosion, and built up trapped sediments.    See appendix A for unit specifications.  The attachment is part of an informational package that is delivered to all visitors of technical demonstration workshops for the UNH SC.  c.)  Self-guided descriptions of innovative storm water management BMP’s An important component of this project was to introduce potential beneficiaries, including municipal, UNH, and state environmental managers to LID approaches to storm water management.  To facilitate this, self-guided informational exhibits have been designed and installed at each demonstration facility in accordance with UNH policies.  The exhibits consist of a steel stand and laminated data sheets describing project objectives, technical design, treatment summaries and contact information, re: UNH Stormwater center.  The signage also acknowledged the NHEP support and the UNH partners.  The exhibits inform interested parties of the scientific rationale, regional impact, and strategic significance of LID storm water management techniques.    d.)  Outreach and education program LID storm water management pilots pose an educational opportunity for many UNH academic program participants.  University undergraduate and graduate students have been directly involved in LID construction, hydrological assessments, and native plant selection.  Two environment and engineering classes have visited the demonstration sites so far.  The number of participants exposed to project results through UNH Stormwater Center technical workshops have been tracked and total over 860 participants since 2004 as of August 31, 2006.   V.  Estimation of Runoff Volume and Pollutant Load Reduction  Low technology, easily adoptable LID storm water management strategies are a recent phenomenon.   Scientific data validating the adoption of such logical strategies must be documented.  A hydrological assessment and estimation of the regional impact is necessary to the continued adoption of such approaches and is provided in this report.   a.)  Volume Reduction To quantify rainfall volume reduction, rainfall runoff curves were used and compared with three months of rainwater catchment/re-use data collected at the UNH Stormwater Center facility.  In general one inch of precipitation on one square foot of impervious surface yields 0.6233 gallons of runoff.  Thus 1,000 ft2 of impervious surface will yield an average of 623 gallons of water.  A 10% initial reduction collectable runoff volume is generally assumed to account for initial abstraction and loss due to inefficiency in conveyance systems.  The calculation used to determine total runoff catchment potential is thus:  Runoff = Area (ft2) x Rainfall (in) x 561                                    1000  7 Collection at the UNH Stormwater Center:   Rainfall conditions, water collection and reuse were measured over a 3-month period at the Stormwater Center installation (Table 1).  The collection area for the 550-gallon cistern installation was 200 ft2.  Due to the small, demonstration size of the facility all rainfall any rainfall collected was subsequently used for drip irrigation reuse.      Month Rainfall (in) Runoff (gallons) Rainfall Collected Runoff Reduction June 4.45 499 499 100% July 2.53 284 284 100% August 2.39 268 268 100% Table 1: Measured water collection and re-use for the UNH SC installation  Collection at the UNH Jackson Estuarine Laboratory:  The 550 gallon cistern was installed just prior to winter 2005/2006.  The collection area consisted of a 10 ft length of gutter installed on the far southern rear corner of the laboratory building yielding a relative collection area of 400 ft2.  Due to the small, demonstration size of the facility all rainfall any rainfall collected (Table 2) was subsequently used for non-potable water needs.      Month Rainfall (in) Runoff (gallons) Rainfall Collected Runoff Reduction June 4.45 998 998 100% July 2.53 568 568 100% August 2.39 536 536 100% Table 2: Estimated water collection and re-use for the UNH JEL installation  b.)  Pollutant Load Reduction The impervious watershed treatment area for the JEL Bioretention tree filter consists of 6,086 ft2 of impervious surface.  Pollutant loading calculations are determined using the EPA spreadsheet method (EPA, 2005) with NURP contaminant loading rate estimations (EPA, 1983).  Bioretention tree filter removal efficiencies have been calculated using existing field data collected by the UNH Stormwater Center (Table 3).    TSS (mg/L) NO3 (mg/L) Zn (mg/L) Loading 253.7 3.22 1.14 Removal 248.6 1.54 1.13 Effluent load 5.07 1.67 0.01 % Reduction 98% 48% 99% Table 3:  Pollutant BioretentionTree Filter Pollutant Load Reduction     8V  Conclusions   This project demonstrates the effectiveness and efficacy of low technology LID strategies for stormwater management and control on the UNH campus.  The demonstration projects have already been a feature in many important site visits and on-going local programs including visits from Governor Lynch, NHEP funded estuary cruises, and UNH SC technical workshops.  Many of these educational programs are on-going and will continue to benefit from the functionality of the demonstrational installations developed through this project.  The source and runoff reduction strategies represented by the rainwater harvesting cisterns and drip irrigation system proved to be effective strategies to control runoff at its source.  Many impervious surfaces provide great opportunities for runoff collection and reuse strategies.  In the JEL cistern installation, the quantity of rooftop runoff was only limited by the size of the collection system.  Opportunities for the expansion of such source reduction strategies can be supported by the findings in this study.  The augmentation of the JEL freshwater supply for non-potable uses was also a critical benefit for this remote facility that depends on well water.  The biorention tree filter installation at the UNH JEL facility remains the only stormater management device employed at the facility.  Its potential for contaminant removal and educational impact has been well established and will remain an asset for years to come.  As the plants, including the grass and Viburnum shrub, mature, more effective filtration of contaminants and uptake of nutrients is expected. The immediate benefit of reducing flow down the walkway stairs has eliminated erosion problems and decreased the weathering of walkway materials, both of which will reduce maintenance costs.  The installation has also eliminated most of the runoff from the parking lot from reaching the estuarine waters.  VI  References  U.S. EPA (2005).  “Handbook for Developing Watershed Plans To Restore and Protect Our Waters.” U.S. Environmental Protection Agency, Washington, DC. www.epa.gov/nps/watershed_handbook/pdf/ch09.pdf U.S. EPA (1983).  “Results of the Nationwide Urban Runoff Program Volume I – Final Report. Water Planning Division.” U.S. Environmental Protection Agency, Washington, DC.    9 APPENDIX A  The following specification documents are part of an informational package that is delivered to all visitors of technical demonstration workshops for the UNH SC.  10 11 

Low Impact Storm Water Management Projects at the University of New Hampshire

https://scholars.unh.edu/cgi/viewcontent.cgi?article=1277&amp;context=prep

Low Impact Storm Water Management Projects at the University of New Hampshire

Abstract

Similar works

Full text

Available Versions

UNH Scholars' Repository