It takes a village: Managing water in a time of climate change
September 20, 2022
Everyone has a part to play when it comes to managing a healthy watershed, especially in a changing climate
Scientists caution that climate change, and the increasing number of extreme weather events, will significantly impact our water resources. In recent years, weather patterns have changed so much that rainfall is not as predictable as it once was. Many places are getting most of their annual rainfall in a few intense events while the rest of the year is dry.
This change might not seem significant, but our existing dams were not designed to accommodate these extremes. Instead of slowly gaining and releasing water throughout the year, in some areas, reservoirs are seeing an influx of a year¡¯s worth of rainfall in one intense storm.
What should dam operators do during these extreme weather events? In most cases they open the dam gates to release excess water. This prevents water from spilling over the top and prevents the dam from failing entirely. But, if they open the gates, they¡¯re losing water¡ªvaluable water needed in dry months.
There are many stakeholders who can contribute to a sustainable watershed. We can design for excess water, store as much water as possible, and be responsible water stewards.
Extreme rainfall, combined with extended drought seasons, is impacting the way we manage water in and around cities.
Designing for excess water
This is where urban planners step up¡ªby planning how the city fits into the watershed and how water moves in and around the city. The closer buildings, parking lots, and asphalt roads are to the reservoir inlet, the quicker large amounts of runoff will enter the reservoir. Impervious surfaces¡ªlike concrete and asphalt¡ªneed to be evenly distributed across a watershed, instead of being concentrated in specific locations. When distributed it slows down the movement of water. This concept allows for sustainable development while mitigating the increased flow and timing of water entering the reservoir.
Green spaces within a city are also important. In a dense cityscape, think of green spaces like small sponges. The vegetation can soak up some of the water where it slowly drains into the groundwater system, instead of running off as stormwater and entering a reservoir.?
Scientists caution that climate change, and the increasing number of extreme weather events, will significantly impact our water resources.
Some urban areas even plan for water collection in and on areas that typically would have just been a source of runoff water. For example, landscape architects can incorporate water-absorbing green roofs where appropriate. Some locations that are prone to flooding might want to consider porous asphalt. As the name suggests, water slowly seeps through roads and parking lots instead of running off or pooling up.
Lastly from a planning perspective, designing how the city will grow can lessen flood consequences. Planners can limit urban expansion to areas outside of potential flooding areas. Landscape architects working together with engineering designers can create more resilient watersheds that help to minimize the impact of climate change to our reservoirs.?
Incorporating green spaces into cities is a good way to reduce runoff into nearby reservoirs.
Storing as much water as possible
Sometimes, dam owners can raise the height of the dam to accommodate for more intense rainfalls. Though, this solution isn¡¯t always a viable option. So, we need to think about managing the water before it enters the reservoir. Upstream management measures can be innovative and cost-effective solutions. For instance, several detention ponds can be built to temporarily store the incoming water and gradually release it to reduce the pressure on the main reservoir during an extreme event. Appropriate measures can vary from one watershed to another. But ponds might be a simple and cost-effective solution.
While detention ponds offer a potential solution, there are also drawbacks. First, dam owners often don¡¯t own the upstream lands in the watershed, so trying to build a dam and manage water on someone else¡¯s land might not be possible. Second, adding upstream detention ponds increases the risk downstream. If a smaller upstream dam failed, it would release that water all at once, adding greater strain on the main reservoir dam.
If building a pond or additional reservoir isn¡¯t feasible, there could be a middle-ground approach of reclaiming or expanding wetlands. A wetland area can provide a natural buffer to soak up excess water upstream of some reservoirs. Wetlands also bypass the two major concerns of the built temporary detention ponds. They may be easier to get permission to create or expand, and there is less risk since there are no additional dams to monitor.
Wetlands are already natural buffers along coastal areas to collect water. Creating or expanding wetlands upstream of reservoirs can help reduce the inflow.
We can be responsible water stewards
Community members can play a big part in water management. Think of your own backyard like a mini sponge. With weather forecasting, we can all be aware of rain patterns and could even be notified not to water our lawns and outdoor plants before an extreme rainfall event. Some sprinkler systems run from a timer and will go at the same time every day even if it¡¯s raining! With weather forecasting, we can all be aware of rain patterns and could even be notified not to water our lawns and outdoor plants before an extreme rainfall event. Water that is absorbed into your yard makes its way into our groundwater system instead of flowing directly into a reservoir.
Is your house a good fit for a rain barrel? Capturing all the water we can helps with the extreme swings in annual precipitation patterns. Watering plants around your house with water stored in a rain barrel is a good option. Do not discount your role in managing our limited water resources. We all play a part!
Actions as small as planning when you water your lawn can make a big difference in helping manage water flow in and around cities.
Learning from our ancestors
Some of the most sustainable and effective measures are not necessarily the most high-tech. Humans have been managing water for centuries. In arid climates, people adopted effective means of storing water to survive droughts. Listening to¡ªand learning from¡ªprior experiences can encourage adaptive solutions. This is critical for us as we cope with a changing climate.
Having a rain barrel or timing when you water your lawn might seem like they will have a small effect on an entire watershed. But small acts add up. Each action can help us better adapt to the changing climate.
In the energy and resources industry, we talk a lot about the need for integration. Different experts and people coming together to solve a common problem, and this is no different. Changing along with the climate and coming up with integrated solutions is critical for all of us.