After a dry summer and despite a few recent rainy days, Connecticut is experiencing an increasingly dry autumn, with areas of the state ranging from abnormally dry to extreme drought conditions. Mike Dietz, UConn extension educator and Director of the Connecticut Institute of Water Resources, spoke with UConn Today about the current drought and how it is impacting homeowners and local water resources.
How long has the current drought been going on, and how bad is it?
We measure the water year from Oct. 1 to Sept. 30 each year, and as of right now for this water year that just finished, we were about six inches behind for the whole year, which isn’t a huge deficit but most of that deficit came in the last few months.
We had a wetter than normal fall in 2019, then winter was fairly dry, then we had a little rain in the spring, followed by two really dry periods this summer, with the driest being the most recent one. Having that hit right now and the time of year when the evapotranspiration is high — where plants are pulling water out of the ground and transferring it to the atmosphere — that is what really brought water levels down to these record low levels in our streams and rivers.
Because for the overall water year we weren’t super low, most of the reservoirs for major water suppliers in the state are in pretty good shape. Mansfield Hollow is probably at one of the lowest levels I’ve seen it recently, but I haven’t heard any notifications from them. Other suppliers have put out notifications to cut down on water use, but they are not at emergency levels.
However, when you are talking about shallow wells and rivers and streams, they are more susceptible to this recent drought. Recently, we had record low flows. In over 80 years of monitoring by the United State Geological Survey, we saw the lowest flow ever recorded on that day on the Mount Hope River, so it was a big deal.
What is the water cycle like in Connecticut, in general?
In some places it really depends on the geology and soil conditions. Connecticut soils tend to hold water pretty well. In some places in the state, water moves slowly through the ground and in some places more quickly. The water is moving down, but it is also moving laterally. That laterally moving water is what feeds into the streams, and since it has been dry, there is less of that water feeding into streams and that is why they are so low at the moment.
For example, around the Willimantic and Fenton rivers we have stratified drift aquifers — where much of UConn’s water is withdrawn — which are really high yield, in that water travels through them really quickly. On the other hand, at my house, the soils are tighter and it takes the water longer to move down through the soil to get into the bedrock where my well is.
Can you talk a little about wells and ground water in Connecticut?
In Connecticut we have a depth-to-bedrock that it is fairly shallow and saturateable, meaning it holds water pretty well. Old hand-dug wells were typically 15 to 20 feet deep. That is as far as you would need to dig down to contact that shallow ground water layer where soil is saturated with water.
Any new well is drilled into the bedrock, so it excludes that water from the shallow layers because those layers are vulnerable to contamination. We have so many people living here now, and along with agricultural activities, and sources of industrial contaminants such as gas stations — waste and runoff would contaminate shallow wells.
Now, to drill a well we have to go into the bedrock, drilling down hundreds of feet to contact fractures in the bedrock, which is how water comes into the well, it enters through those fractures. Water takes a tortured path from the surface down through the soil, through fractures and into the bedrock to end up being in a well where it can be pumped out.
How long will it take for our water supplies and wells to recover from the drought?
It will depend on the soil and how deep the well is. If your well was going dry, these last couple rainstorms will not fix that problem. That water will make its way down, but it will not raise the levels appreciably.
What will help is the trees are going into dormancy now. They are not pulling water out of the ground through evapotranspiration, our temperatures are lower, and that will help raise our ground water levels.
Trees are a huge portion of our water budget here in Connecticut. About half of the water that falls over the course of a year gets evaporated or taken up by the trees from the soil and sent back up to the atmosphere. Most of it happens during the growing season, about six months out of the year.
If we do have more dry conditions through the fall and into the future, then I think we really will start to hear some of our big water supply reservoirs starting to get pretty low, and we will start to get some impacts on a larger scale.
The recent Connecticut Institute for Resilience and Climate Adaptation (CIRCA) Physical Climate Assessment Report projects increasing variability in precipitation events, with “potentially very dry summers and others may be exceptionally wet” by mid-century. What can we do to become more resilient when faced with variability?
To prepare for dry conditions, if you have not done so already, be sure you have upgraded to low-flow fixtures in your house. For example, low-flow faucets and shower heads, and low-flow toilets.
If you irrigate your lawn — you really shouldn’t — look into turf species that have lower water and fertilizer needs. We have research out of the UConn Plant Science department on turfgrass which highlights grass species that have lower water requirements.
In regards to people with wells, if you don’t have any water issues now and you have a drilled well and it’s not giving you trouble when it gets very dry, I’m not sure there’s much you can do beyond the standard water conservation measures.
On the other end of the spectrum, in addition to more drought, we have seen and expect to see more extreme events in our region. This means that newer stormwater designs that incorporate infiltration (rain gardens, pervious pavements, etc.) will become increasingly important, to help mitigate heavy precipitation.