Water Resources

Designing Drainage Systems for Renewable Energy Sites

By Henry Meeker, Senior Graduate Engineer, WSB

When designing drainage systems for renewable energy sites, many different surface water factors must be considered to ensure a well-constructed system. These factors include how floods can impact the site, how water damage affects equipment and access points, soil erosion, water regulations, and how runoff impacts the surrounding ecosystem.

Floods can cause both widespread and deep channelized flow across solar farms.

Designers need to understand how water will flow across the site in different flood scenarios. Many renewable energy sites are located near floodplains, which can make the design process even more complicated. To tackle these challenges, WSB engineers use sophisticated 2D hydraulic models to map the direction, depth, and speed of water flow across the site.

Stop water damage to critical site components.

A crucial part of the drainage systems design process is ensuring that water, in any scenario, can flow smoothly across the site without causing any damage or flooding to critical components, such as inverters or battery storage units. Designers use the results of the hydraulic models to find the best solutions for water flow and to place these critical components away from the main flow of water. The models are also used to identify areas where water flows too quickly. WSB develops erosion control measures in these situations, such as reinforcing road surfaces at low water crossings.

Plan for ground erosion around solar panel support piles.

Another important aspect of renewable energy site design is ensuring that the supports for the solar panels can withstand strong winds and flooding. Each site is unique, our engineers work closely with our clients to use the results of the hydraulic models to assess the potential scour depth, meaning the point in the ground where erosion could occur, around the support piles and identify the appropriate methodology to use. This determines the best depth for embedding them. The models can also be used to identify areas where water is flowing too quickly and to develop erosion control measures, such as rock stabilization.

Consider water quality and management regulations.

Designers also need to consider regulations around stormwater management, water quality, floodplains, wetlands, and critical species/habitats. Project timelines will be significantly delayed without proper planning and consideration of these factors. WSB works to minimize the impact of the site on these sensitive areas while ensuring that the project proceeds on schedule. This often involves working closely with local government units and obtaining the necessary permits.

Protect ecosystem health.

Designers must understand how solar panels interact with the surrounding vegetation and soil. Major institutions, like the University of Minnesota, are performing ongoing research into how panel runoff affects water infiltration and an ecosystem’s health that will be incorporated into designs. Designers can leverage these findings to optimize water quality benefits for the site, incorporating water quality basins, pollinator-friendly vegetation, and site-specific erosion control measures.

How WSB Can Help

Do you need help planning your solar project and navigating challenges around drainage water systems? WSB can help with your design, develop erosion control models, ensure protection of local ecosystems through sustainable solutions, and more.

When the Leaves Fall: Proactive Leaf Management Tips for Communities

November 15, 2022
By Jake Newhall, Project Manager, WSB

Autumn is in full swing. While the arrangements of red, orange, and yellow are stunning, the mass collection of leaves that enter a city’s sewer system after a rainfall can cause serious damage – from clogs to flooding to pollutants in our waterways. 

When the Leaves Fall

When leaves fall, especially when followed by heavy rainfall, leaves on roads, sidewalks, and other impervious services can wash down into city sewers. When the leaves break down and decompose, the nutrients they contain can end up in water. This leads to harmful algal blooms and degraded water quality in rivers, streams, lakes, and other water bodies. 

Additionally, too many leaves washing down stormwater systems can also clog pipes and drains, cause localized flooding, and lead to expensive maintenance costs for cities. 

How can cities proactively address fall foliage and prevent these issues? Here are some tips and tricks. 

Targeted Street Sweeping

The first thing communities can do to avoid these problems is establish a targeted street sweeping plan which analyzes and maps impervious surfaces and high tree canopy coverage areas, as well as their proximity to high-value water resources. Street sweeping is one of the most cost-effective methods to reduce pollutant and nutrient loads to waterbodies and can be very helpful in achieving TMDL goals.

While leaf fall can happen at different times each year depending on several factors including weather, an efficient street sweeping plan prepares communities to manage and strategically target optimum leaf removal.  

Community Education 

Another thing communities can do to help prevent leaves from clogging drains and entering into waterways is to educate residents and private property owners about best practices in autumn. Raking leaves, bagging them, clearing the gutters near private properties, Adopt-a-Drain programs, and properly disposing of the leaves can go a long way in reducing the total amount of nutrients in our waterways and leaves in storm drains. 

How WSB Can Help 

Not sure where to start with creating a targeted street sweeping plan? WSB can help create a customized street sweeping plan that meets your community’s needs. WSB can also help communities reach their pollutant removal goals and execute on water quality management. 

WSB Announces Jake Newhall Promotion to Director of Water Resources

November 28, 2022

WSB, a Twin Cities-based design and consulting firm specializing in engineering, community planning, environmental, and construction services announced Jake Newhall’s promotion to director of water resources. 

As director, Newhall will assume day-to-day operations of the water resources group as well as focus on strategy, business development, and setting operational goals with company leadership.

Throughout his tenure at WSB, Newhall has been instrumental in shaping the growth of WSB’s water resources team. His well-rounded skills and experience have allowed him to solve some of the firm’s clients most complex stormwater management challenges.

“I am proud that I have the opportunity to grow my career at WSB,” said Newhall. “For more than 16 years, I have worked at WSB with a focus on solving complex stormwater and water resource related problems. I look forward to serving in this new leadership position, advancing strategic initiatives to expand our firm and delivering unparalleled results for our clients.”

WSB’s water resources services balance engineering, ecosystems and social impacts to create sustainable water infrastructure.  The firm offers services in stormwater, floodplain management, lake and stream habitat restoration, water quality monitoring and more. Additional information about WSB and its services are available at wsbeng.com

Communities Can Prepare for Flooding and Build Resilience into Systems

By Jake Newhall, Project Manager, WSB

Extreme rainfall events are occurring with increased frequency. Due to climate and environmental changes, many cities and communities are facing an increased flood risk and must act to protect their communities, residents, and infrastructure. A 2019 report by the National Institute of Building Sciences noted that Natural hazard mitigation saves $6 for every $1 spent on infrastructure resilience.

How can community planners, engineers, and elected officials prepare for and protect their communities from flooding? Here are some guidelines to help reduce flood risk in your community when a storm hits.

Preparing for and Understanding the Weaknesses in Your Systems 

Flood vulnerability and resiliency studies are a process for evaluating a community’s ability to withstand rainfall and identify flood risk. These studies look at the existing systems and determine the risks, and where improvements can be made to protect priority infrastructure. This is vital for communities to reduce risks and flood damage to property and public infrastructure – especially in densely populated areas and those near major roadways. 

As we face more extreme weather events, communities should consider increased rainfall depths and intensities so they can be proactive in system planning. The current storm probabilities available have not been updated since 2014, yet rainfall trends show increases over the last decade. Communities can greatly benefit if they anticipate the future probabilities of storms and construct systems that can handle more intense rainfalls. Using a range of design storms, you can determine flood depths, frequency, duration and assign risk to help prioritize funding. 

Completing a risk analysis and inundation mapping utilizing existing modeling can be a low-cost way to start evaluating your system.

Identifying Projects to Reduce Flood Risk

Locating the areas of risk in your community is critical to flood prevention. That could include finding where your system needs more capacity and storage to reduce flooding, determine what properties are prone to flooding, and creating solutions such as relocation, emergency response, or additional flood protection investments. 

Where collected water goes is important when examining and determining updates for your systems. The primary options are to either pass the water downstream into creeks and rivers, or store it in drainage ponds, underground systems, or other storage areas. Another option is to reduce the impervious footprint to reduce the amount of runoff that is generated. Emerging technology allows for predictive rainfall systems that can generate additional storage ahead of a large rainfall event by releasing water early and prior to a peak event through a critical area.

The risk with moving the storm water downstream is the possibility of flooding and eroding the creeks and rivers. If conveyance capacity is increased to the downstream system, it is necessary to make sure that proper measures are taken to avoid flooding and erosion that can harm waters and ecosystems. Water storage options like drainage ponds or underground storage, are options for many communities to utilize. Balancing needs, functionality, and the cost of storage and land is important for communities to explore. Water quality and pollutant removals can be a secondary benefit of many stormwater storage systems that can help communities achieve other goals at the same time.  

Finally, for most communities, the needs often outweigh the budget available to accomplish them all. WSB helps clients navigate flood vulnerabilities, pursue grant funding, and help make informed decisions that best serve a community’s individual needs. 

Water Sustainability and Community Planning

By Alyson Fauske, Sr Project Manager, WSB

Last summer, Minnesota experienced a drought due to above-average temperatures and below-average precipitation. This created a significant challenge for many community leaders and public agencies. To keep up with demand, wells were pumping at or near capacity over much of the summer, and communities were forced to implement water restrictions for the first time in decades. Some cities banned lawn sprinkling all together, though this is not water sustainability.

Heading into 2022, Minnesota is still facing drought conditions in some parts of the state. There are a number of things that communities and public agencies can do to plan for and respond to drought conditions using sustainable water planning.

Limit Water Usage

In drought conditions, limiting water usage is critical and often the first step taken. Communities can help limit water use by developing water reuse systems and plans. They can also implement landscaping practices that require less watering including native plants and drought resistant plantings and grasses. Native plants also have the added benefit of supporting local wildlife health and helping to protect pollinator populations.

Tap Into Local Grants & Resources

In 2021, the Minnesota Department of Natural Resources (DNR) put together a Drought Assistance Proposal. This proposal includes a request for $13.3 million in funding to help cities address the effects of last year’s drought. WSB is tracking the funding package as it moves through the legislature and will be prepared to assist clients with grant applications for any approved funding, as well as identify other funding opportunities that are tied to this effort.

Long Term Water Sustainability

A significant portion of the budget for the Drought Assistance Proposal is set aside for proactive water conservation measures that would help combat the effects of potential future droughts.

Municipal engineering and sustainability go hand in hand. Municipal engineers develop plans and projects that maintain infrastructure, considering the whole life cycle of the project while aiming to minimize the amount the taxpayer needs to provide to routinely maintain the infrastructure.

Proactive water conservation measures allow communities to be better prepared for the next potential drought. These measures may consist of finding and repairing leaks, increasing irrigation efficiency, or incentivizing residential and business customers to install water-saving devices.

Climate change and a greater risk of drought impacts community planning, and leaders who implement sustainability measures that are proactive, and not just reactive to an immediate crisis, will fare better in managing drought.

If you want to learn more, contact Alyson Fauske, Senior Project Manager at 612-263-1736 or [email protected].

Reasons municipalities implement water restrictions

Alyson Fauske, Sr Municipal Project Manager, WSB

In Minnesota, also known as the land of 10,000 lakes, many people wonder how even in times of severe drought, we don’t have enough water. As of early August, over 35% of the state is now experiencing extreme drought conditions. These drought conditions significantly impact municipal water supplies.

The type of water that cities supply to their residents is treated for a number of economic and environmental reasons. Cities around the state measure the annual average demand and peak demand, but drought conditions like we’re experiencing now, fall outside of annual averages.

In the last several weeks, many cities have implemented additional restrictions, and many residents don’t understand how these restrictions can help restore water levels within a matter of hours. Although it doesn’t seem like limiting irrigation or water use would have much of an impact, it significantly improves a city’s supply.

Enacting water restrictions alleviate the demand and can prevent communities from falling below fire protection and boil water levels. The below diagram shows an example of a water tower’s levels in a week. Water towers have censors that measure elevations. There is a minimum water level within the water tower to provide adequate fire protection. In our example, that level is 21 feet, meaning if there were a fire and the water tower level was below 21 feet there may not be adequate supply to fight the fire. 

There is also a minimum level that needs to be maintained in the water tower to ensure that the pressure in the system is high enough to keep contaminants from entering the water system. In our example, if the water elevation drops below 10 feet a boil water notice would be implemented. 

There are several actions that communities are taking today to help limit water usage including developing water reuse systems and plans, adjusting landscaping to include more native, drought resistant plantings and grasses, and reducing overall water consumption.

Instances of severe drought remind us that water is not a limitless resource and that forces outside of our control can have major impacts on our infrastructure.  

Solving Complicated Water Issues

The Minnesota Pollution Control Agency (MPCA) and Minnesota Department of Natural Resources (DNR) recently released their $700 million plan for improving the drinking water supply in 14 communities that are currently dealing with unsafe levels of perfluoroalkyl and polyfluoroalkyl substances (PFAS) in their water. The government’s plan includes building or expanding:

• Six new water treatment plants
• Treating 33 municipal wells
• Connecting 296 homes to municipal water systems
• Providing home water filtration systems to homeowners with private wells

WSB was fortunate to be involved with the city of St. Paul Park to help them find a solution to increasingly dangerous PFAS levels in their community. In June of 2018, the Minnesota Department of Health informed St. Paul Park that the PFAS levels in two of its three water wells was exceeding the recommended levels that are safe for public consumption. WSB partnered with the city to design a water treatment facility and remove PFAS from the community drinking water and surrounding environment.

[pull-quote quote=”PFAS are a family of manmade chemicals that do not naturally decompose due to their heat and water-resistant structure. Studies have found that consuming drinking water with elevated levels of PFAS, overtime, can be associated with high cholesterol, reduced immune response, thyroid disease, kidney cancer and other distressing health problems.”]

After completing a rapid column filtration pilot study, acid-washed granular activated carbon filtration was selected as the most feasible, long term solution to treat PFAS in the city’s drinking water.

1. Steel pressure filtration vessels contain granular activated carbon filter media that facilitate the transfer of contaminants onto the media as the liquid stream passes through the vessels.
2. When the contaminant level in the carbon bed reaches the saturation point, the carbon is removed and regenerated at an off-site facility or disposed.
3. After the media becomes fully absorbed with PFAS, the media is removed from the vessel and refilled with high quality activated carbon.

The project utilized an innovative modeling software, Matterport, to video scan the interior of the plant and provide a three-dimensional layout. This model allows city staff to provide accurate virtual tours of the plant remotely. Matterport also serves as an asset management tool for storing critical operations and maintenance data for each piece of equipment inside the plant. This innovative tool allows staff supervisors to reference and provide instructions to their teams from a remote location. Leveraging Matterport software ensures important equipment data, plant drawings, and schematics can be accessed from any location with Wi-Fi or internet connection.

Great emphasis was placed on the design to protect the environment and provide a sustainable facility. The plant produces almost no emissions that affect the environment other than space heating during the winter months. Nearly no wastewater will be emitted from the plant in the long term other than discharging backwash wastewater into the sanitary sewer system about once every two to three years when the filter media is exchanged for new media. On site, a large oak tree situated about 20 feet from the plant was preserved during construction. Since the plant was constructed in a city park, all areas that were affected by construction were restored with landscaping and grass that creates a natural flow to the surrounding athletic fields.

Since the plant was placed into service, no PFAS contaminants have been detected in the effluent water that is distributed to city customers. The quality of the drinking water has been excellent and exceeds all drinking water and health standards.

How the DNR’s flood risk review could affect Minnesota communities

By Earth Evans, Director of Water Resources, WSB

The Minnesota Department of Natural Resources (DNR), in coordination with local watershed districts, has developed updated draft Federal Emergency Management Agency (FEMA) flood risk maps and hydrologic and hydraulic analysis. The affected area includes the floodplains in the hydrologic unit code 8 (HUC8) subbasin. HUC8 includes portions of Ramsey, Washington, Anoka, and Hennepin Counties.

The updated hydrologic and hydraulic analysis is based on National Oceanic and Atmospheric Administration (NOAA) Atlas 14 precipitation events across the United States. The draft flood hazard maps may expand existing FEMA regulated floodplains within the Twin Cities metro due to the higher precipitation depth and frequency. The FEMA map updates will likely take effect in 2023. This is the first step in the process to develop updated FEMA Flood Insurance Rate Maps.

It is important that city officials pay close attention to these updates. The draft FEMA floodplain boundaries may increase with this analysis, which may reduce developable area in a municipality, increase the number of properties that are required to purchase flood insurance, and require property owners to change the type of flood insurance they possess. Additionally, the DNR is requiring that each community update their ordinance to require mitigation for fill in the modeled storage areas upstream of FEMA floodplains. 

Currently, the maps are for city officials only. City staff should cultivate a strong understanding of the implications now, before the maps become open for public comment. During the next month, there will be opportunities for city staff to connect with the DNR staff, review floodplain limits, and understand the implications on developable area and properties that will require flood insurance within the community. 

WSB can help navigate this process and facilitate meetings with DNR Floodplain Staff. City officials are encouraged to reach out to Earth Evans, WSB’s Director of Water Resources with questions.

Partnering with the city of Hugo to create a sustainable water reuse strategy

By Mark Erichson, Pete Willenbring, Kendra Fallon and Ray Theiler, WSB

About 10 years ago, the City of Hugo was looking for feasible options to reduce the amount of potable water used to irrigate green spaces within the city. At that time, approximately one-half of the water the city pumped from its municipal wells was used for irrigation. The city was also facing the need to add wells, water towers, and treatment to provide enough capacity for this use. Studies indicated the cost for these facilities was going to increase water bills significantly, and the MDNR was reluctant to grant additional groundwater appropriation permits in the area.       

To address this issue, the city and WSB staff developed a list of potential options, and the city commissioned WSB to focus on completing  a series of studies to determine if it would be technically, financially, and politically feasible to collect, store, and re-use stormwater runoff instead of city well water for this purpose. Furthermore, the study was focused on potentially utilizing existing stormwater retention and treatment ponds that are currently in-place throughout the city for this purpose. As part of these studies, initial evaluations focused on the ability to implement this type of program for the city’s largest irrigation users. These evaluations found that providing stormwater for re-use to these users was indeed feasible, and furthermore, when properly set-up, residents were enthusiastic supporters of the practice and program. Following these initial successes, our team began to coordinate with city staff and local partners to fund, design, and construct other reuse systems. 

Reducing, reusing, and replenishing water resources is now a city prioritized conservation practice. All new development projects are required to collect and treat stormwater, and install stormwater reuse systems for irrigation when feasible and practical. This reuse also significantly reduces the volume of stormwater and the pollutant load that is discharged downstream of the sites, further benefiting downstream natural resources such as wetlands, lakes, and rivers. 

We continue to offer guidance about sites that may be a good fit for reuse systems. When these are identified, we work with city staff and the local watershed district to identify and secure grant funding for new projects and encourage developers to implement water conservation practices such as stormwater reuse. Several private developments have been able to take advantage of this partnership, including the Oneka Ridge Golf Course and the Water’s Edge Homeowners Association, a 1,000 unit housing development.  Grants have funded between 25 and 85 percent of reuse projects. Where projects utilize water reuse which exceeds what is required for stormwater management, volume reduction credits are banked. These credits are tracked by the City and can be purchased by developers for future projects where site constraints make onsite stormwater treatment difficult. 

Shifting the public perception of water reuse is important to a project’s success. We partnered with city officials to facilitate neighborhood meetings to educate residents on water reuse and its benefits. Public living in proximity to these reuse projects will benefit greatly by improved water quality in adjacent downstream water bodies, while also reducing reliance on our stressed groundwater resources.

Stormwater reuse offers a number of financial and environmental benefits to the city of Hugo and its residents. By identifying and utilizing alternate water resources to reduce potable water demands, the city is able to reduce the stress placed on its water system, possibly postponing or eliminating the need for additional water infrastructure improvements such as wells, towers and size of trunk watermain facilities.

As groundwater demands increase, Hugo and WSB will continue to work together to change local water use practices and attitudes towards water reuse and water conservation. 

Please contact us to learn more about how to incorporate more water reuse strategies in your community.

Simplifying MS4 compliance through technology

By Jake Newhall, Project Manager, WSB

Minnesota’s Municipal Separate Storm Sewer System (MS4s) are currently in the process of applying for coverage under the revised MS4 General Permit. The updated MS4 General Permit creates changes in the ways that MS4 permittees will operate, starting with modifications that address procedural and programmatic changes needed to comply with updated rules. 

One of the main changes is new performance-based responses to Total Suspended Solids (TSS) and Total Phosphorus (TP); including a TMDL assessment to identify and prioritize activities to achieve reductions. WSB’s SWAMP system helps to address these new regulations by streamlining TMDL compliance through tracking and documenting improvements that have been completed to date or since the baseline of TMDL development. The SWAMP system also helps target subwatersheds that are underperforming or lacking the necessary treatment to meet water quality goals. SWAMP improves efficiency by saving time on planning and modeling when developing an efficient plan to address TMDL requirements.

Aside from improving compliance with new MS4 TMDL requirements, SWAMP continues to help address existing MS4 requirements.

• Estimate TP and TSS reduction from existing ponds and BMPs
• Prioritize inspection and maintenance activities related to ponds and BMPs
  • Ensure standard operating procedures are in place and stormwater management features continue to function as designed
• Inspection and maintenance activities are automatically updated and reflect real-time information
• Tracks and stores completed activity records for on-demand reporting

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