There was a city council work meeting on March 21st to discuss potential problems a proposed Dry Wash reservoir could create. It wasn’t a public hearing, but more than 80 residents attended. Thank you! Your attendance made a difference.
Even though it wasn’t a public hearing, the Mayor invited a number of residents to speak about their concerns. Ivins resident Wayne Pennington spoke and recommended changes to the size and shape of the reservoir that would help mitigate some of the negative impacts. Wayne is a PhD geophysicist and a retired Dean of Engineering at Michigan Technological University. he has done a lot of research on the proposed reservoir on behalf of the community.
He also provided a detailed explanation of the history of the reservoir planning. That was an eye opener. That history shows the current plan is for a larger reservoir than was ever recommended, studied, or discussed.
Listening to Wayne’s history made me think of the story, Goldilocks and the Three Bears. One proposal, namely no reservoir, might be too small. One proposal, like the current 1,500-acre-foot proposal, seems too big. Is there one proposal that’s just right? Wayne thinks so. And his report does a good job explaining why.
Click here for a PDF of Wayne’s report that includes the history as well as his recommendations. Here is a summary of the history from his report along with his recommendation.
A reservoir proposed for Dry Wash has undergone studies by geotechnical engineers and environmental specialists, proposed as the third phase (after Graveyard Wash) of the St George Water Reuse Project. In 2004, they specified that a reservoir at Dry Wash should not exceed 3,040 ft for safety concerns; any larger reservoir would need to be created by a dam further upstream, which was not included in the Environmental Assessment.
In 2021, the Washington County Water Conservation District (WCWCD) agreed to a reservoir of 1000-1200 acre-ft (smaller than the 1335 acre-ft specified by the EA), but the Ivins City Council approved consideration of a larger reservoir. The WCWCD then proposed a 1500 acre-ft reservoir with 3,044 ft high-water level, violating safety concerns expressed by earlier studies due to incompetent rock (soil) at that elevation at the dam site. [I believe that the proposal by the WCWCD likewise violates the conditions of the geotechnical and environmental studies.]
The maximum capacity for a reservoir with a dam at the proposed location and a high-water level of 3,040 ft is 1335 acre-ft (excavation could increase the capacity). But a reservoir with these characteristics would still create problems due to a broad, shallow area on the western flank, creating a mudflat when the reservoir is low, and allowing wind to pick up dust and other materials, carrying it to populated areas.
Mitigation of this problem will require adjustments of dike location, high-water level, and excavation and relocation of the excavated material in strategic locations.
There may be many ways to resolve these issues; one approach, which will allow a trail with open space, is presented in Wayne’s report. His model would have a capacity of about 1000 acre-ft (after excavation), which is a size that had in 2021 been stated as acceptable by the WCWCD and would permit the needed access/egress of westernmost Ivins through the future Anasazi roundabout.
Download Wayne’s 11-page report. This is an important and complex issue, but Wayne makes it easy to understand the problems and possible solutions to at least some of the problems.
Thanks, Mike, for the Dry Wash Reservoir update. You have the much-appreciated gift of translating complex issues into comprehensible explanations. And thanks to Wayne for his extensive work and the use of his considerable professional expertise to document the serious design flaws and safety impediments of the current WWCD reservoir plans.
I’d like to add my own concerns and those of other health care professionals regarding the dangerous dispersion of toxic particulate matter which will occur from the current design of the proposed Dry Wash Reservoir.
The risks of saltation and the production of airborne particles are significant, with toxins such as left-over secondary sewage chemicals, pharmaceuticals, insecticides, pesticides, and forever chemicals transported by windblown dust to surrounding neighborhoods, causing consequential health hazards to Ivins’ citizens now and into the future.
Voluminous medical journal and epidemiological studies detail the adverse health impacts associated with windblown particulate matter, including increased emergency room visits, respiratory illnesses, bronchitis, asthma attacks, heart attacks, and increased incidence of death. Add to that the cancer-causing effects of forever chemicals and the neurodegenerative diseases correlated with pesticides and insecticide exposure, and you have a long-term health crisis in the making.
A community’s health scores, and the public relations nightmare of forever illnesses dotted on graphs surrounding that Dry Wash Reservoir will mar Ivins economic development into the future. No one wants to live in the new Salt Lake with poor air quality and worsening human health stats. Stewarding the environment and protecting human health will positively affect the quality of life for Ivins citizens in the short term and the long term.
The Washington County Water Conservancy District and Ivins City have been notified in advance of the adverse health impacts and dangers to the surrounding communities from the Dry Wash Reservoir. It is neither ethically permissible nor fiscally responsible for the city and the WCWCD to proceed with the plan as currently designed.