Education, Licensure and Certification (2)
Ph.D.: Civil Engineering, Marquette University 1993
Registered Professional Engineer: Wisconsin and Illinois
Associate Professor William Gonwa has worked in the fields of wastewater collection, storm water management, and flood protection since 1984. He received his doctorate from Marquette University, his masters from the University of Kentucky, and his bachelors from the University of Wisconsin-Madison, all in civil and environmental engineering. Dr. Gonwa is on the faculty of the Milwaukee School of Engineering (MSOE). He started as a part-time adjunct professor in the Masters of Science in Environmental Engineering Program in 2002. In 2010, he accepted a full-time appointment in the Civil and Architectural Engineering and Construction Management Department. As of the fall of 2019, Dr. Gonwa has been serving as the program director for the Civil Engineering degree. Prior to 2010, Dr. Gonwa spent 25 years as in consulting engineering at CH2M Hill, Crispell-Snyder Consulting Engineers, Symbiont Science, Engineering, and Construction, including two years volunteering In Panama doing development projects. Dr. Gonwa still assists Symbiont on a part time basis. He is a registered professional engineer in the State of Wisconsin. Dr. Gonwa is fluent in Spanish having lived and worked in Mexico, Panama, and Peru for several years. In his spare time, Dr. Gonwa has advised the Global Brigades and assists with the Engineers Without Borders organizations at MSOE. He enjoys riding bicycle for pleasure and commuting, and plays clarinet in the Wauwatosa Community Band.
Areas of Expertise (5)
Water Resources Engineering
HydroLearn Fellow (professional)
Best Technical Presentation, Illinois Section American Water Works Association Watercon
- Central States Water Environment Association
- Illinois Water Environment Association
- Water Environment Federation
- American Society of Civil Engineers
Media Appearances (1)
Grass Roofs are Becoming Popular Energy Savers Around Milwaukee
Living Architecture Monitor
"It's a great idea. You get multiple benefits," said William Gonwa with MSOE. From the ground, you'd never know there's a garden on the roof of MSOEs Grohmann Museum. Gonwa says it does so much more than look pretty.
Research Grants (7)
Water Environment Research Foundation Grant to Document the Effectiveness of the Greencastle
Indiana Private Property I/I Reduction program
Grant to Design, Build, and Monitor a Pervious Pavement Parking Lot in the city of Milwaukee
Grant to Document the Effectiveness of the Greencastle, Indiana Private Property I/I Reduction Program
Design of Residential Storm Water Infiltration Practices
Milwaukee Metropolitan Sewerage District
MSOE Pervious Pavement Parking Lot
Milwaukee Metropolitan Sewerage District
Miller Brewing Bioretention Swale and Rain Garden
Milwaukee Metropolitan Sewerage District
Efficient Real Time Control and Operation of Interconnected Wastewater Collection Systems
Milwaukee Metropolitan Sewerage District
Selected Publications (5)
Using Full Factorial Analysis to Enhance Water Quality Monitoring ProgramsNWQMC Sixth National Monitoring Conference
Gonwa, W.S., Byers, H.L., Koltz, B.J.
2008 Statisticians use a group of techniques collectively called "Design of Experiments" when designing a sampling program. A formal experimental design can multiply the information gained from a sampling program many times over an informal design. Full Factorial Regression Analysis is one such technique particularly useful for designing stream or river sampling programs. Full Factorial Regression Analysis collects all sampling data in n-orthogonal dimensions at two or more levels in each dimension. For example, upriver and downriver from a potential contaminant source could form one of the dimensions, collected at two levels. Wet weather and dry weather could form another dimension, also at two levels. Collecting data in orthogonal patterns allows sample to be used in multiple paired comparisons and maximizes the ability to determine the causes of data variability. In addition, Full Factorial Regression Analysis permits assessment of factor interaction. This paper provides a background on the Full Factorial Regression Analysis technique used to design a water quality sampling program and analyze the data. It discusses the use of regression analysis to process data and overcome the problem of missing samples. Lastly, it highlights two sampling programs designed and analyzed with Full Factorial Analysis. The two programs, one conducted on the Mississippi River by the City of Rock Island, Illinois and the other conducted on the Illinois River by the City of Peoria, Illinois were designed to document the effects of combined sewer overflows on water quality in receiving waters with multiple pollution sources.
Private Property I/I Control Program in Greencastle, IndianaProceedings of the Water Environment Federation
Gonwa, W.S., Nitka, J., Morrow, G.
2008 The City of Greencastle initiated an infiltration/inflow (I/I) reduction program to reduce I/I from private property sources in 2003. Greencastle's I/I policy requires certified inspectors to document that privately-owned properties do not contribute excessive rain water to the sanitary sewer systems. Residential properties are inspected upon requests for a new water service, which typically occurs upon change of ownership. Non-residential properties were required to be inspected within two years of program initiation and have been completed. If an inspection finds a defect, property owners must either fix the defect immediately or apply for a waiver. A waiver can only be granted when fixing the defect is impractical or too costly. Compliance inspections typically cost 30 to 50 and are scheduled and paid for by the homeowner.The policy is making a difference. After just a few years in effect, WWTP operators noted lower average daily flows and lower peak flow rates. Prior to implementing the policy and companion public side I/I removal efforts, rain events would often cause peak flows of 16 million gallons per day (MGD). Currently, heavy rains are needed for peak flows to exceed 5 MGD. Before the policy, the treatment plant would need to treat increased flows for several days and sometimes weeks after a rain event. Now, operators observe that treatment plant flows return to normal within 24 hours. Manholes that frequently surcharged to the surface prior to implementing the policy now do not surcharge. The City views the policy as an unqualified success at reducing I/I in the collection system.The United States Environmental Protection Agency (USEPA) and the Water Environment Research Foundation (WERF) jointly funded a program to document the effectiveness of the I/I reduction program. In the spring of 2007, Greencastle installed flow metering at four of locations that had been metered prior to initiating the I/I reduction program which allowed a comparison of pre- and post-rehabilitation flow rates. This paper reviews the design of the program, provide an update on the implementation of the program, and presents data documenting costs and benefits.
Preventing Increased Infiltration/Inflow from Residential Storm Water Best Management PracticesProceedings of the Water Environment Federation
Gonwa, W.S., Ellis, S.D.
2006 This paper discusses design criteria and guidelines for the placement of three types of residential storm water best management practices: rain gardens, downspout extenders, and rain barrels. Guidelines are needed to prevent unintended increases in private property infiltration and inflow (I/I). These guidelines specifically focus on soils and construction practices typical of the Milwaukee, Wisconsin area. The rain garden investigations were designed to determine the recommended distance between a raingarden and a house's sewer lateral. The field experiments consisted of a series of 100 square foot simulated rain gardens placed at increasing distances from the sewer lateral. Rising groundwater levels or soil moisture content at the sewer lateral during a test indicated the potential forincreased I/I. As a result of the field experiments, the investigators recommend placing a rain garden at least 10 feet away from the sewer lateral or house foundation in the silty clay soils typical of the Milwaukee area. Placing test rain gardens at this distance resulted in no impact on soil moisture at the sewer lateral. If groundwater mounding occurs, it is unlikely that any increase in infiltration into leaky laterals will occur within the critical time frame for sanitary sewer overflows. The downspout investigations were designed to determine the recommended length of a downspout extender. The field experiments consisted of simulating rainfall discharge through downspout extenders of different lengths. Increased flow in the house's foundation drain indicated the potential for increased I/I. Downspout extenders that discharged at least 5-feet away from the house foundation resulted in no increase in drainage to the house foundation. As a result of the field experiments, the investigators recommend using a minimum of 5-foot-long downspout extenders in the siltyclay soils typical of the Milwaukee area. Ten-foot-long extenders are preferred. The rain barrel investigations were designed to determine guidelines for draining rain barrels into planting beds adjacent to house foundations. The field experiments consisted of simulating rain barrel discharge through weeping hoses of different lengths while monitoring the discharge through the foundation drain. Increased flow in the house's foundation drain indicated the potential for increased I/I.
Efficient Real-time Control and Operation of Interconnected Wastewater Collection SystemsETD Collection for Marquette e-Pubs
1993 One of the most cost effective methods for limiting sewer overflows and flooding is to actively control the sewer system, operating it to fully utilize available storage, conveyance and treatment capacity. Such requirements are now included in sewerage utility discharge permits. Installing regulators, such as moveable sluice gates and weirs, allows sewer operators to control flows, but can cause problems such as increased risk of flooding. These regulators require efficient control logic to meet operational objectives and constraints. Algorithms are developed to solve several typical control problems in inline and diversion gate control. One algorithm controls an inline gate to maintain a desired flow rate or upstream water level. Another algorithm determines the diversion flow required to achieve a desired flow rate or water level in the main sewer. Another set of algorithms determines required flow rate at a control structure to achieve a desired flow rate or water level at some downstream location where substantial delay exists between the control action and its effect. All algorithms are based on water level measurements and are implemented with a minimum of mathematical and controller complexity. Fuzzy control methods are proposed where conflicting operational objectives and qualitative information exist. Portions of the Milwaukee Metropolitan Sewerage District (MMSD) collection systems were modeled to assess algorithm performance. The few hydraulic models theoretically capable of simulating a sewer system subject to control are unstable and execute slowly. An improved model, based on the zero-inertia approximation, was developed to test control algorithms. The zero-inertia model assumes no inertial components in the governing equations for flow, the St. Venant equations, but can model backwater effects and flow reversals. The recommended algorithms are stable and can maintain elevated flow rates and water levels with little risk of flooding. Fuzzy control successfully balances conflicting objectives and manipulates qualitative information. The potential for substantial benefits from improved control of the MMSD collection system is demonstrated. The zero-inertia method is demonstrated to be a stable, accurate, and rapid method for simulating sewer systems subject to control.
A Modified Diffusion Equation for Flood Propogation in Trapezoidal ChannelJournal of Hydrology
Gonwa, W.S., Kavvas, M.L.
1986 This study on the diffusion equation was performed to gain new insight into the adequacy of the analytically solvable linear diffusion equation which is used as an approximation to Saint-Venant's equations for flood routing in open channels. The derivation of the diffusion equation was approached assuming a variable trapezoidal channel cross-section, variable channel slope, constant lateral inflow, a generalized velocity—depth relationship and the diffusion approximation to the full Saint-Venant's momentum equation. A new modified diffusion equation was obtained which theoretically accounts for channel and wave variations resulting in new non-linear expressions for the wave celerity and diffusion coefficients. Numerical testing on a linearized version of the modified diffusion equation shows that the assumption of constant values for the parameters of the diffusion approximation yields inadequate flood routing results. Since the assumption of constant wave celerity and constant diffusion coefficient in the diffusion equation amounts to the linearization of the equation, the numerical results of this paper show that the linear form of the diffusion equation is inadequate for flood routing. Therefore it is necessary to consider the non-linear form of the diffusion approximation to Saint-Venant's equations as an approximate model for flood routing.