Nebraska has many communities with declining populations. This decline can create problems for communities to fund projects or maintain wastewater facilities. Based on these observations, Nebraska determined that a tool was needed to adjust engineering designs, establish schedules, and prioritize efforts.
Assessing Wastewater Infrastructure Needs (AWIN) is a model used to determine the risk of a community’s sustainability. The AWIN model was developed by the Nebraska Department of Environmental Quality (NDEQ) with assistance from EPA’s Environmental Finance Center at Wichita State University. This model uses demographic data, such as population changes, age group trends, employment, and housing, to obtain a sustainability risk number. A high AWIN number indicates that a community may face greater challenges for long-term sustainability. A datasheet is generated for each community in Nebraska and is available the NDEQ website at http://deq.ne.gov.
An example of the AWIN process: Alexandria, Nebraska, population 177, needed to replace its wastewater treatment system. The community was at high risk for long-term sustainability under the AWIN analysis. The initial wastewater design selected was for 13 acres of complete retention lagoon, which included a population growth buffer. NDEQ, the consultant, and the community looked at the AWIN analysis and projected a decline of more than 20% of the population in 20 years. Based on this and discussions with the community, the design was reduced to seven acres. A 17-year compliance schedule was agreed upon with options for temporary irrigation to be used as needed. The project was built along with some sewer rehabilitation and is now operating as a complete retention facility. By not overbuilding, project savings were $160,000 to $200,000.
Other Results to Date:
- The Nebraska Emergency Management Agency Hazard Mitigation Grant Program used AWIN to rank communities for grant awards.
- The Clean Water State Revolving Fund uses AWIN as the new affordability criteria.
- AWIN helped determine that the Median Household Income (MHI) in rural areas can be inaccurate. For example, Waterbury had a published MHI that was about $20,000 higher than actual. This MHI error made the difference between the community receiving a small town assistance grant or not.
AWIN continues to evolve, and NDEQ is working on ways to refine it to assist with decisions involving affordability, project priority, compliance terms, and engineering options.