Top Projects 2019

The Kitsap County Public Works Department (KCPW) in Washington state has transformed a vacant former trailer park into a fully operational storm water facility to improve downstream water quality and hydrologic conditions in Clear Creek and Dyes Inlet. 

What at first was supposed to be a large storm water retention pond has been turned into a multi-benefit regional storm water retrofit facility called Whispering Firs that uses green treatment techniques to treat runoff in a way that meets current Washington State Department of Ecology water quality standards.

Project Manager Chris May said the facility treats total suspended solids (TSS), total petroleum hydrocarbons, metals and nutrients and reduces flows to Clear Creek, which is the main salmon-bearing stream in the north Dyes Inlet. 

Coming off the successful implementation of the Manchester Stormwater Park, KCPW decided to use a similar retrofit design for Whispering Firs to expand it beyond just a retention pond. Both facilities now use Filterra filter media manufactured by Contech Engineered Solutions for their tree-box filter systems. The team said the engineered-soil mix provides enhanced water quality treatment at high-flow rates by using high-performance treatment cells.This allows for the treatment of large drainage areas – more than 100 acres each for this project. 

Keeping water quality treatment and flow control at the forefront of the plans, the team minimized water depth by using a pressure head so that dirty water would be intercepted from the basin and pushed into the treatment system through a closed conduit flow. In the end, all dirty water rises to the park surface at approximately the same elevation, which allows for shallow treatment cells, according to the team. Additionally, they created a flow control splitter configuration that isolates treatment cells.

“As with all retrofit projects, construction in areas with existing infrastructure are challenging due to engineering and site constraints, as well as utility conflicts,” May said. 

The $4 million project treats 113 acres of high-use roadway and residential areas. It was made possible by a team of engineers, landscape architects and permitting officials and the Washington Department of Ecology, who provided $1.5 million in grant funding. 

The design choice allows the property to not only treat storm water to current standards but also provides public access. In addition to its four large, high-performance treatment cells, two bioretention cells and two wetland ponds, the facility has walking paths, picnic areas, bird and wildlife habitats and offers views of the Olympic Mountains. Additionally, native plants are located throughout the park that naturally cleanse the water. The plants are small now, but eventually, they will grow and should make the park look like a wetland.

“This system will have direct positive benefits for Clear Creek, Dyes Inlet and Puget Sound,” May said. 

The team said the park conveyance system is designed to accommodate a future connection that would permit additional water from a separate developed drain basin with inadequate water quality treatment to enter the park and be treated. 

Overall, the team is most proud of the fact that they were able to provide water quality treatment at current Washington state standards for more than 100 acres of older development, while also providing a park-like amenity for the community. 

Sustainable Vegetation Prevents Further Erosion 

When more than 20 acres of land were burned in the California Freeway Fire, an emergency restoration project was deemed necessary. Daniel Reynaga, CPESC, QSD for Profile Products, said it is crucial to reestablish vegetation after wildfires to avoid any further land damage. 

So, a team worked toward multiple goals: establish sustainable vegetation to avoid post-burn dangers; apply the proper solution on the first try as it used public funds; amend the soil to create optimal growing conditions; and safely apply an erosion control product to hold seed and soil in place until germination. 

Hydrophobic conditions on the soil surface can lead to high erosion rates as a result of poor infiltration and debris flow. Because of this, the first step in the project was to conduct a soil test, which showed the site had low organic matter, between 1.5 and 2.2% daily. Reynaga said a site should have ideally more than 5% organic matter. Instead of bringing in topsoil or compost, the team decided to use biotic soil media, hydraulic erosion control products and soil analysis. Those, along with seed mix, were hydraulically applied together using one hydroseeding machine. 

"This project proves that these new technologies that are being developed are working with great success across the West Coast when it comes to emergency fire work and producing sustainable vegetation,” Reynaga said. 

Using one hydroseeding machine cut down the time and labor it would have taken to apply the solution with incorporated compost. 

The project was deemed a success, and within three months, the site was covered in a blanket of purple and yellow wildflowers. 

Culvert Combats Intersection Flooding in South Carolina

During times of heavy rain, the intersection of Ebinport Road and Northgate Lane in Rock Hill, S.C., would cause yard flooding and property damage to five residences. A box culvert was installed under the intersection in 2007, but the yards continued to be damaged. After an analysis, it was found that the culvert was undersized, which was resulting in roadway overtopping.

A project was implemented to limit overtopping of the existing creek banks to assist with flood mitigation and minimize property damage. The team decided to go with a large, regional impoundment area to control flows to a newly constructed dam and culvert with the advantages of additional flood control for a majority of the 70-acre watershed the intersection drained into, which also established a natural floodplain and wetland area.  

After the easement acquisition and Phase 1 environmental assessment were completed, construction began with the installment of sediment and erosion control BMPs. Once the dam was completed, the site was fine-graded, seeded and strawed or matted for stabilization purposes.

At first, the culvert opening was determined to be larger than the design intended, the excavated areas were not as deep as required and several trees that had been planted within the existing sewer easement needed to be shifted. After the models were re-run, a steel plate was designed for the front of the culvert to restrict flow and velocity downstream. 

Green Practices Aid Storm Water Plans

The city of Cudahy, Wisc., is both an MS4 community and part of the Milwaukee River Basin TMDL., meaning it is required to remove suspended solids and phosphorus from storm water runoff that flows into Lake Michigan and the Kinnikinic River. The city is also committed to integrating green infrastructure practices into public works improvement projects that will include high-performance permeable pavement systems and vegetated biofilters, Project Manager Todd Weik of CBC Engineers said. 

In 2016, the public works department was developing projects to replace an alley, called the Green Alley, the public Squires Avenue Parking Lot and the front of the city hall parking lots because of deterioration, all of which are in close proximity to redevelopment.

The city was introduced to air-cooled blast furnace slag (BFS) to use as a phosphorous control product. Based on past steel slag experiences, the city’s solid waste staff was hesitant to use BFS. Weik said there were concerns over pH levels and potential impact on freshwater fish. An ecotoxicity test showed a mortality rate for water fleas and fat head minnows of less than 5%. Based on these findings, department staff approved BFS as long as it was contained. 

The city chose to use a permeable articulating concrete block to capture and transfer storm water under the alley and city hall parking lot. The subsurface aggregate storage gallery was made with semi-permeable geotextile membranes that allowed the water to pass through them at a rate of 175 gpm. High-performance biofilters were used to meet the water quality needs of the Squire Avenue lot. 

Cudahy officials have implemented a three-year monitoring program of the discharge for both project areas. Specific storm water catch basins were identified as sampling locations, and an early sample from the Squire Avenue lot and Green Alley shows that the ortho phosphorus has been eliminated and the total phosphorus has been reduced by 90%. 

Low Impact Development BMPs Replenish Groundwater 

In an effort to replenish local groundwater supplies and reduce potential pollutant discharges to the municipal storm sewer system, CASC Engineering & Consulting retrofitted a 1.7 acre commercial development office site to capture and infiltrate runoff. 

Despite the low permeability of the top soil, low impact development (LID) BMPs were implemented to cover more than 100% of the site. The LID BMPs include two infiltration basins, two infiltration trenches, two areas of pervious paving, one area of pervious interlocking pavers, one roof-runoff diversion system and three areas of turf conversion. These practices reduced the site’s storm water discharges, increased infiltration and reduce potable water.

Through the project, employees gained a better understanding of runoff reduction by creating drainage management areas and using the rational equation to compare pre- and post-improvement drainage conditions. 

Before the retrofit, 100% of the site drained directly into the street or adjacent creek. Now, only 14,983 sq ft drain to those areas, which is a 79.6% reduction. There has been an 11% reduction in runoff capture design volume. The project also reduced water usage by removing 10,877 sq ft of turf and installed drought tolerant landscaping. 

“We eliminated over 11,850 sq ft out of the total 21,200 sq ft of water-loving turf and converted it into a system that virtually eliminated storm water discharges from the site and will contribute to the recharge of the local groundwater basin,” said Chris Sidor, project engineer with CASC.

Redevelopment Project Incorporates Creative Storm Water Tasks

In the 1950s, an industrial complex that housed the Verdelli Farms vegetable processing facility was built in the Hummelstown borough in Pennsylvania, but in 1993, it permanently shuttered, leaving the the 5-acre property vacant. 

As redevelopment efforts have increased, along with the need for housing opportunities, a property named VERDE was developed to include six new residential buildings, parking, a fitness center, a maintenance building, four multi-car garages, sidewalks and more.The redevelopment strategies had to match the neighborhood’s existing context, meet storm water regulations and comply with all applicable environmental requirements. 

Given the borough’s green infrastructure and storm water management requirements for peak flow attenuation and nutrient discharge reduction, creative storm water planning was integrated into the design process.

Hummelstown sits within the Chesapeake Bay watershed and because the site is underlain with karst geology, specialized hydrologic modeling was needed to represent the runoff associated with these areas. Four water-tight underground storm water facilities and conveyance infrastructure improvements were implemented. Additionally, project officials conducted a water quality analysis and implemented BMPs for the removal of total suspended solids, nitrogen and phosphorus in accordance with the General NPDES permit requirements. 

“The Verde project is an important and replicable example of urban redevelopment that implements a number of cost effective solutions for developers and communities to consider,” said Len Bradley, P. E. with RGS Assn. Inc. 

Data-Driven Monitoring Tackles Cleaning

When faced with a U.S. EPA Consent Decree with an estimated cost of $1 billion, the San Antonio Water System (SAWS), adopted the EPA’s Capacity, Management, Operations and Maintenance guidelines. 

It instituted high-frequency cleaning—monthly, bimonthly, quarterly, semi-annually and annually—for 110,000 manholes and pipeline segments whether those sites needed cleaning or not. 

Without underground visibility, sewer operators routinely cleaned the same pipes, which resulted in a “high-frequency cleaning cultures.” 

SAWS wanted to switch from a calendar-based cleaning system to a real-time, condition-based one. It wanted to decrease wear and tear on pipelines and refocus resources, such as time, labor and money, on other activities.

To do so, it integrated SmartCover’s data-driven monitoring and decision support to improve its understanding of the system, optimize cleaning routines and protect human and environmental health. 

Since implementing the SmartCover system, there have been 65 cleanings, a decrease from the previous 1,246 cleanings. SAWS has seen a 95% reduction in cleaning and zero sanitary sewer overflow incidents with 216 sanitary sewer overflow (SSO) “saves,” which equates to more than $1 million in savings based on the average spill cost of $5,000.

In addition to these benefits, human and equipment resources were freed for other needs, risk to staff and SAWS’ carbon foot print were reduced, and management now has access to more data to prioritize capital investments. 

The the results have not only lowered cleaning costs while preventing SSOs, but SAWS also was able to deploy a smart infrastructure solution with fast payoff and stable ROI.  

Detention System Halts Flooding on Boston College Campus

The Lower Campus area of Boston College is the hub of activity with some important buildings in its vicinity, such as the Alumni Stadium, Conte Forum, the Fish Fieldhouse, the campus police and others. 

However, because the school was built into the side of a hill, the verticality of the campus and its underground drainage systems cause the Lower Campus to suffer impacts from rain events. Two to four times per year, the campus can be inundated with up to 3.5 ft of flooding. 

Jacob R. Murray, PE, LEED AP and senior civil engineer with Waterfield Design Group, said sand bags and portable pump brigades were often utilized at a moment’s notice as the campus’ flooding trigger was measured by rainfall intensity, not volume. Additionally, the city's storm water infrastructure does not have an outlet for collected storm water to exit the Boston College system. 

After analysis, an underground detention system with a watertight basin was built and designed under the Fish Fieldhouse with the capability of storing approximately 2.5 million gal of storm water that can provide 25 years of flood protection for the campus. 

More than 7 acre-ft of underground storage had to be installed inside the college’s athletic field house to store runoff from the two main flooding areas—the Alumni Stadium and the Beacon Street parking garage. More than 680 StormTrap units were placed in a 65,000 sq ft footprint. 

“This project illustrates firsthand the value that effective storm water management can have on the bottom line of a major institution,” Murray said. “Spending money on storm water management is not as glamorous as building new classrooms, dormitories or athletic fields, but without these important improvements, the utility of each of those elements within the Boston College system were threatened.”  

Flood Bund Protects Residences from Damage

After a large flooding event impacted a farm, workshop and a private house on the River Wyre riverbank, property owners sought out a solution. Over the span of a year, a plan was developed for what would be the most suitable option. A simple redesign showed a raised flood bund and additional features could prevent flooding.  

The local Flood Action Group (FLAG), comprised of village volunteers who have all suffered from flooding in the past, was a driving force in securing funding and gaining approval and publicizing the project to fellow residents, said David Grayston, of project owner Floodsafe.

FLAG reached out to various charities, and the Environment Agency provided a contribution. 

For the project, precast concrete flood blocks were implemented. The final design of the project covers more than 500 flood defenses with a combination of earthen raised bund through agricultural land and a 1.5-meter high modular block wall. The project is complete with gates and demountable barriers where the line comes closer to a domestic property. 

The hollow blocks, which are laid on a reinforced concrete strip foundation, allow for steel reinforcements and concrete infill to be used, resulting in quick installation and protection for the surrounding property.

In the end, this solution protects the entire village of Churchtown in Lancashire in the United Kingdom, not just the three original properties. 

“The range of methods and products employed means the scheme blends in with the environment in a very pleasing way,” Grayston said. “In the end, the program is far more worthwhile than how it was first envisaged." 

Green Infrastructure Aids Los Angeles in Storm Water Management

Trash, sediments, heavy metals and fecal indicator bacteria are polluting the Los Angeles River. 

The surrounding areas lack efficient storm water infrastructure, so a project was developed for the city of Los Angeles Sanitation Environment (LASAN) to improve the quality of the Los Angeles River water to meet provisions of the Municipal Separate Storm Sewer Permit. 

Project Manager Wing Tam said the project is part of LASAN’s Green Streets Initiative for the GSI Program, which aligns with the mayor’s sustainability plan and other watershed management plans to protect water quality in local water bodies, reduce flooding and improve water reliability and climate change resiliency. 

The project incorporated various green infrastructure elements, including 21 dry wells, nine bioswales and 11 porous concrete gutters. 

Tam said to meet standards, the project is designed to reduce localized flooding, remove pollutants, such as trash, metals and bacteria and increase groundwater recharge in the San Fernando Groundwater Basin, which is currently at less than 50% of its storage capacity. 

Tam said the team is most proud of the partnership between local and state agencies, the use of innovative materials and the simple yet modularized design. 

“LASAN feels that the project set a perfect industrial benchmark and demonstrated how a GSI project can be implemented (concept to completion) within 18 months,” Tam said. “Additionally, a one-year optimization (or start-up) phase is incorporated into project scope, which allows the project owner and contractor to ensure that the project performs as intended.”