- Completed December 31, 2018
The population of the Twin Cities metropolitan is projected to increase by an estimated 818,000 between 2020 and 2050. Because of the proliferation of lawn irrigation systems, the summer to winter monthly water demand ratio in many communities has increased from 2:1 to 3:1 or even 4:1. This increase in peaking factor is driving the need for new water supply wells.
In cooperation with CDM Smith consultants, we worked with fifteen communities to obtain financial data on current and forecast (through 2040) capital and O&M costs for well installations. We also obtained financial data on the costs of implementing irrigation system audits, sprinklerhead replacements, native landscaping, and EPA WaterSense-labeled ‘Smart’ Irrigation Controllers. Then, an Excel spreadsheet-based financial model (the Water Efficiency Potential Tool) was created to compare an ‘As-Is’ with a ‘Efficiency’ scenario for each community.
The ‘As-Is’ scenario calculated the present value costs of the estimated of new wells through 2040. The ‘Efficiency’ scenario calculated the present value costs of implementation of selected water efficiency measures, along with the present value costs of the delayed and/or reduced number of new wells through 2040. The difference in present value costs between the two scenarios was compared to determine, for each community, the financial gain or loss realized by the community.
Under the scenario where the utility covers 100% of the cost of the efficiency measures, fourteen communities realized a financial gain through some combination of efficiency measures. In total, twenty-one wells were eliminated for these communities at a savings of $20.7 million.
Under the scenario where the utility covers 50% of the cost of the efficiency measures, all fifteen communities realized a financial gain through some combination of efficiency measures. In total, twenty-two wells were eliminated for these communities at a savings of $26 million.
- Growing communities could save millions of dollars by funding outdoor irrigation efficiency measures, thereby eliminating and/or delaying water supply well installations.
- Our Water Efficiency Potential Tool can be used to estimate savings to communities.