Cost-effective, high-volume flood control and bypass water pumps can mitigate climate change effects of excess stormwater and groundwater if coastal cities act now
More than 99% of today’s U.S. population in 252 coastal communities will have their homes submerged by 2050 if left ignored.1 That’s more than 126 million people and 40% of the U.S. population.2 But how can flood control and bypass pumps help ebb the tide against Climate Change?
Many coastal communities have a long history of stormwater flooding with varying solutions to handle it. Unfortunately, sea level rise due to climate change is quickly making these 100-year storm plans inadequate. The 100-year storm used to be a maximum limit, but now cities are hitting that mark more often and facing higher water volumes than ever before due to increasing storm severity and frequency. Additionally, due to saturation and sea-level rise, coastal cities that are already at or below sea level during high tide are facing excessive erosion and higher groundwater tables. This means there is a greater risk of everyday “sunny-day flooding” if the water cannot be stored or dissipate into the ground fast enough.
The desire to live close to large bodies of water, be it a river, lake or the ocean, has always been a draw to homeowners—but at what risk? This often leads to overdevelopment and densely populated coastal towns. By building more homes but continuing to overtax the water collection system, cities’ infrastructure is failing them, and municipalities are not focusing on the big picture. Unfortunately, many cities are built on antiquated, gravity-fed sewer systems that are ill-equipped to handle the larger demand. Due to age and stress, if there are leaks in the system or if rain and sewage is combined, rainwater entering the system adds to the volume of water that needs to be treated by a wastewater treatment plant before it can be discharged, which is a costly endeavor.
What are cities municipal responsibilities to their residents in response to climate change?
Some cities have invested the time and money to strengthen their infrastructure. Combined sewage overflows (CSO) is one solution, whereby large underground storage tanks handle excessive stormwater events so that contaminated water does not escape without being treated. This system provides the temporary storage of water until the system can catch up, but as storms get stronger the capacity needed will grow. Another cost-effective solution is pressurized sewage systems. Instead of the costly replacement of underground sewer pipe with wider pipes, the system uses existing pipework to pass larger volumes with higher pressures via pumps like submersible electric pumps found in lift stations. Yet another solution would be to invest in separating sewer and stormwater systems. Since it is more expensive to treat sewage than stormwater, this option lowers the amount of sewage that needs to be treated and cuts down or eliminates the need for overflow storage from excessive rain events. Sewage bypass pumps can help in the aid of building a secondary system while repair or replacement work is being done to the existing sewer system, or to help route flows when a new one is built.
Homeowners near coastlines choose to accept the risk that they are within a 100-year floodplain or a Federal Emergency Management Agency (FEMA) flood zone, but they are not aware of what that truly means until severe weather or tidal event directly affects them. They simply expect their city to have plans to guard against water issues, but what are the cities responsibilities? Severe hurricanes, tropical storms, and seasonal events (such as king tides in Miami) could mean knocked out or overloaded water, sewage or electrical systems, flooded roads or basements, and costly damage claims. Plus, larger and more frequent storms can and will require added pumping capacity for communities as well as irrigated lands to remove additional water. Excess water can also become a threat to a city’s fresh, potable water in the form of saltwater intrusion which is the movement of saline water into freshwater aquifers, that can lead to groundwater quality degradation, health hazards and compromised sewage plants.3
To better protect their cities, municipalities must accept climate change, review what mitigation strategies are available for both short and long term, analyze what steps they can take within their budget and begin to implement plans to save their citizens. Water pumps can be a key element in helping cities to mitigate damage and losses. In the short term, when higher seas do not allow water to drain as easily, high-volume portable flood control pumps can provide temporary or seasonal protection to bring water levels down pre-storm and remove localized flood waters post-storm. For long term proactive solutions, temporary to permanent, fully integrated stormwater pump stations provide an economical, fast, and efficient system that can save time and money.
Temporary to permanent solutions to handle excess stormwater and groundwater
Solutions to saving communities from sea-level rise run the gamut from temporary to permanent and at varying cost. Some temporary fixes include the use of mobile pumps to move flood waters after the storm and portable flood walls/barriers that can be used to protect individual buildings or parking lots. More advanced municipal storm water pumping stations can also be easily and quickly installed with minimal civil works in a matter of days, saving more than 30% of the time and money it would cost to build traditional flood control structures.5
One of the biggest ideas is to defend the shoreline by building sea and retaining walls. Unfortunately, efforts like these redirect erosion elsewhere creating the need for more sea walls or trapping water against the walls which could do more harm than good. Furthermore, building seawalls is costly, unsustainable, unappealing and temporary since the average life span is only 25 to 30 years and the pounding or rising of water will ultimately make then ineffective. Alternate plans to building solid sea walls include creating natural infrastructure buffers or “a living shorelines” via mangroves, reefs, marsh, beaches and seagrass that helps to break up large storm surge while slowing land sinkage.
Time is running out: Planning, budgeting, cost and time are needed to protect against sea-level rise
More costly and difficult plans include raising buildings and roads, vacating the first floor of buildings, replacing degrading infrastructure, strengthening codes or building elevations, homeowner buyouts and relocating residents or entire towns. A good example of critical structures that will need raising or relocating are pump stations. High-volume water pumps can act as the filtration or wastewater treatment pumps within the station but can also be used for pump station bypass to keep the water flowing while the station is rebuilt, raised or relocated. Additionally, engineering will be necessary to help cities prepare its infrastructure. This is seen as no return on investment by decision makers since money is spent on planning and not actually building anything. Progressive pump companies often can help with this problem by providing free, in-house certified engineering and support for flood control pump planning and water mitigation strategies.
These options are time consuming, costly and would require federal, state and local support as well as funding that go beyond what individual communities can do alone. Most towns do not have a master plan for a long-term water mitigation strategy. Many rely on a reactive approach to do what they can fix now and then deal with longer term plans if there is left over funding. Unfortunately, most state and federal funding is based on a reactive approach. A good example is FEMA’s approach to help communities rebuild from disasters after a storm but does not provide the same funding to prevent imminent destruction from happening before a storm hits. With a proactive approach to protection, and careful planning, every $1 spent on disaster mitigation can save $6 in disaster relief.6 High-volume water pumps are critical elements of a two-pronged solution. They can help with the short-term reactive approach by removing water after the storm or helping bypass while work is being done to existing structures. Pumps can also become a foundation for a long-term proactive approach of aiding in building stronger, water-proof communities with permanent pump stations and protection for the future.
This article was written by MWI Pumps Marketing Manager, Brett Climan and published as the cover story by Pumps & Systems Magazine in their February 2021 issue.