Of all the environmental issues that demand our attention, there may not be a more challenging one than management of water. It’s not as “sexy” as PFAS (Per- and Poly-flouroalkyl substances), as controversial as Waters of the United States, or as eye-catching as enforcement, but it is becoming increasingly important.
Managing water in urban environments is not new. However, it’s becoming more of an issue as the population continues to grow, weather patterns change, and the amount of urbanized land with impervious surfaces continues to increase.
Urban Environments and Water
In one of my undergraduate textbooks (Urbanization and Environment, 1972), which I kept for some unknown reason, water management was one of the main themes. In this book, the authors state, “The range of effects resulting from the failure to incorporate storage areas in urban drainage systems…include an increase in the frequency of flooding; reduction of groundwater recharge…and increase soil erosion due to higher flow velocities.”
Mind you, the global population in 1972 (when the above referenced book was written) was about 3.8 billion with 37% of it being urban. The 2020 population is nearly 7.8 billion with 56% urban. These significant changes have had a substantial impact on water management.
Too much water or not enough water – both can, and do, have enormous and life-altering consequences and can lead to litigation.
Litigation of Water
My colleagues at Dragun have, for many years, provided litigation support on projects where the amount of water was the issue. Our technical support has included (a) evaluation of the effects developments have on surface water drainage, (b) evaluation of whether new developments (agriculture and residential) will have enough water to meet the demand, (c) analysis of the risk to new water uses from nearby contamination sources, (d) interaction of landfills and drainage improvements, (e) distinguishing between ephemeral and permanent streams, (f) responsibility for increased surface water, (g) responsibility for increased groundwater, and (h) development and groundwater levels.
In the fall of 2019, we provided expert testimony in a jury trial. In this instance, the plaintiff claimed excessive water from a nearby development had negatively impacted his property. Our testimony was instrumental in exonerating our client.
Typically, when we are asked to evaluate the issues related to excessive or insufficient water, we start with two of our senior staff: Dr. Michael Sklash (hydrogeologist) and Matthew Schroeder, M.S., P.E. (engineer). Below, we have a short question-and-answer session with them that discusses some common issues related to water extremes:
- What is the role of groundwater in flooding?
Before the mid-1970s, the general thought was flooding was all related to rain or snowmelt. Isotopic investigations have since shown that groundwater discharge during storm and snowmelt events is a very important contributor to flooding. This discovery has helped to explain the chemistry (such as acid rain runoff and legacy nitrate issues) of flooding streams.
- What data are important in determining the causes for excess surface water?
On a big scale, increasing sea level, increased storm intensity, and land subsidence contribute to floods in coastal areas. For smaller catchments, understanding the role of groundwater discharge during storms and the relationship between precipitation trends and groundwater levels are important in understanding flooding issues.
- Recently, many areas have been dealing with a lot of surface water. What are the regulatory and permitting considerations with too much water?
For entities discharging wastewater or stormwater to surface water bodies, the higher water levels can cause backups in the system if the hydraulic grade gets “flipped.” We are seeing regulatory agencies requesting or requiring analyses of the system’s vulnerability to high water levels as part of the discharge permit. In another example, the higher water levels will expand the areas for which wetland permitting requirements apply under Section 404 of the Clean Water Act.
- How does excessive water affect slopes?
We often hear about landslides in mountainous areas during storms. Heavy rain facilitates landslides by adding weight directly to the soil. In addition, higher groundwater levels can reduce soil shear strength and can facilitate movement in zones with a pre-existing tendency to slide.
In many shoreline areas, higher lake levels have caused damaging shoreline erosion. This is caused by wave action plus the factors discussed above that induce landslides.
- How can excessive groundwater withdrawal affect streams?
Groundwater and streams are symbiotic. Too much groundwater withdrawal can lead to streams drying up. Too much groundwater can result in an overabundance of groundwater discharge to streams, causing soggy areas around streams that were previously dry.
- Can excessive groundwater withdrawal impact utilities?
In extreme cases, it’s easy to imagine. In places like central California and eastern Texas, land subsidence due to groundwater withdrawal has caused the land surface to sink 10, 20, or 30 feet, resulting in serious issues with sewers, canals, water, and gas pipelines, etc.
- When there is subsidence from excessive groundwater withdrawal, is this reversible?
Most of the subsidence resulting from groundwater withdrawal occurs because porewater moves out of clayey units. This causes a re-arrangement of the clayey soil particles. Many studies have shown that this trend is not reversible (you can’t introduce water into the clay units and pump them up like a tire).
Litigating Water Can Be Complicated
Litigating the amount of water, whether too much or not enough, often requires a multi-disciplined approach and evaluating many factors. The lawyer who retained us in the project last fall (mentioned above) said, “You guys did a great job. We talked to the jury and the testimony of both of you mattered and they were impressed.”
If you would like more details on the topics covered, or if you need expert services on a project involving water-related issues, you can contact Mike or Matt at 248-932-0228.
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