Green infrastructure’s impact on regional water quality

Gray from the beginning

Urbanization in America grew exponentially in the first part of the 20th Century, primarily due to the increase in industrialism (steel mills, factories), as well as increased immigration from Europe. Over the last century, fantastic feats in architecture and engineering have included sprawling highways built to connect the coasts, buildings that touch the sky, and concrete channels ensuring our massive cityscapes have access to water.

While these inventions are impressive, we are learning more about the impacts of gray infrastructure and urban areas on our environment. Approximately 70% of greenhouse gas emissions worldwide come from gray infrastructure. These dense, urban areas also cause the urban heat island effect, which directly affects our energy intake, increasing temperatures and health issues. 

Image via Pexels

One of the predominant issues caused by gray infrastructure is poor water quality. During heavy rains or snowstorms, stormwater falls to the surface. In urban areas, this water falls into gray infrastructures such as pipes, channels, and sewers which can result in sewage getting into our water.

Gray infrastructure often plays a role in directing stormwater into our water sources, so stormwater does not return to the earth where pollutants are eliminated. This is where green infrastructure (GI) comes into play.

What is green infrastructure?

The Water Infrastructure Improvement Act defines green infrastructure as “the range of measures that use plant or soil systems, permeable pavement or other permeable surfaces or substrates, stormwater harvest and reuse, or landscaping to store, infiltrate, or evapotranspirate stormwater and reduce flows to sewer systems or to surface waters.”

In essence, green infrastructure can store and infiltrate stormwater and prevent or lessen its impact on water systems used in urban areas. One example of green infrastructure is green roofs. These roofs are covered with plants and vegetation that allow rainfall infiltration and evapotranspiration of the stored water. These are extremely beneficial in urban areas and cost-effective. It does not involve much construction; it simply allows these gardens to bloom on top of the already constructed gray infrastructure.

Image via Pexels

Another popular form of green infrastructure is bioswales. Bioswales serve as an alternative to traditional concrete gutters and storm sewers. They also serve as a form of beautification, as they are much more aesthetically appealing than standard drainage systems; they create a more natural appearance in an otherwise extremely urban landscape. Bioswales use vegetation and plants at ground level, allowing the soil to absorb stormwater. They can assimilate local and native plants specific to an area, leading to a potential home for wildlife.

Smaller green infrastructure helps with water quality as they are cost-effective and clean soil and water of potentially dangerous contaminants. This process is called phytoremediation, and it involves filtration, extraction, stabilization, and stimulation, with plants serving as a filter for contaminants such as lead, aluminum, and arsenic. With the right soil and plants, these seemingly “small” projects can have a large cumulative impact.

These are just a few examples of the many possibilities green infrastructure presents. Each of these brings different benefits and aesthetics, helping to improve water quality. These limit stormwater runoff that could potentially affect drinking water or water that is a habitat to wildlife. While gray infrastructure allows runoff to flow freely, green infrastructure prevents runoff and thereby improves our water quality.

Working with water quality and green infrastructure

Here at Watearth, water resources are our bread and butter. We are extremely passionate about improving water quality through the use of green infrastructure. Watearth takes on numerous projects every year that focus on stormwater management and control.

In the Houston, Texas area Watearth worked with the Harris County Flood Control District (HCFCD) on their Green Infrastructure Stormwater Control Measure Backslope Swale Stream Stability Retrofit of Flood Control Channel project. This project included retrofitting and restoring native vegetation in the riparian portion of urban flood control channels. Watearth evaluated hydrology and water quality improvements using GI retrofits. EPA Storm Water Management Model (SWMM) Low Impact Development (LID) models were developed to evaluate the effectiveness of modifying a backslope drainage system to be considered an Integrated Management Practice (IMP) that meets green infrastructure criteria and enhances surface water runoff.

Watearth also worked with the Los Angeles County Public Works (LACPW) on the Adventure Park Regional Stormwater Capture and Integrated Water Resources project. Watearth took on numerous roles for this project, including designing a rain garden. Also known as a Biofiltration area, the rain garden features plants that thrive in dry and wet climate conditions, and it serves as a filtration system for Adventure Park’s surface runoff. The rain garden collects and filters park pollutants such as chemicals, oils, and debris. This was intentionally designed and constructed in an area of the park to capture as much runoff as possible.

If you would like to learn more about Watearth and our services, please visit our website. We are happy to discuss your stormwater and green infrastructure project needs.

CEQA Initial Study Outcomes: What you need to know

CEQA – or the California Environmental Quality Act – was passed in the State Congress and signed into law by then-Governor Ronald Regan in 1970. CEQA was a direct response to the federal government passing the National Environmental Policy Act (NEPA) some months prior. These policies both exist to ensure environmental protection.

CEQA requires state and local governments to inform the public about environmental impacts of proposed projects, and to try and reduce these impacts when possible. It’s important to understand how CEQA works, as well as the benefits of this act.

What is a negative declaration?

If a project is believed to not cause any detrimental impacts to the environment, a negative declaration (ND) can be declared. It can only be stated after filling out the CEQA checklist (which includes topics such as aesthetics, agricultural research, and air quality) and acknowledging there will not be significant environmental harm. An ND is issued after the initial study (IS) has been prepared and is a “positive” project outcome.

The opposite of a “positive” project outcome is a “significant adverse impact” outcome, meaning considerable environmental damage is possible if the project is approved. Land, water, air, wildlife, mineral resources, and cultural resources could be at great risk, and should be avoided if possible.

Once a project is approved with a ND, a Notice of Determination (NOD) is filed at the county clerk’s office saying the project does not have a significant impact on the environment in which the project is taking place.

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What is a mitigated negative declaration?

A mitigation measure is required to reduce or eliminate environmental damage caused from building by a project. An example is if a development caused tree removal, then a requirement could be to redesign the project to save more trees and strategize how to replace any trees that could not be saved. A mitigated monitoring and reporting program (MMRP) is required by California law and ensures mitigation measures are properly carried out and environmental damage will be prevented or lessened.

If a significant impact is identified that cannot be mitigated, an Environmental Impact Report (EIR) is required. Significant impact is defined as a substantial adverse change in the location’s physical conditions. If you must prepare an EIR, it goes to the lead agency and then to public review (generally within a month). Next, the lead agency will prepare a final EIR including a response to comments provided during the public review. Finally, the lead agency responds to public agencies within a minimum of 10 days before the EIR is certified.

CEQA is important—it helps prevent potentially significant damage to the environment, while also allowing communities affected by projects to have a voice in decisions. It also enables stakeholders to take a big-picture view of the project.

Watearth and CEQA

Here at Watearth, we frequently work with CEQA, have staff that specialize in CEQA, and have successfully completed numerous projects involving CEQA.

Our work with the City of Oakland for their Mosswood Community Center CEQA project involved creating the Initial Study (IS) gathered topographic data, and developing a preliminary design recommendation along with other project documents. Additionally, Watearth conducted CEQA analysis and drafted technical memorandums.

We also have significant experience in creating EIRs. In southern California, we worked with the City of Los Angeles Zoo assisting with their Master Plan and Zoo Vision Plan EIR Hydrology and Water Quality Technical Studies. We prepared water resources and sustainability sections of the Master Plan and the EIR. This included NEPA/CEQA and water quality impacts to the Los Angeles River.

Deck overlook surround by vegetation and shallow pool of water
Image from Watearth’s LA Zoo project.

We also worked with the Los Angeles Bureau of Engineering (LABOE) on their Venice Auxiliary Pumping Plant (VAPP) EIR Hydrology and Water Quality Technical Studies project. On this assignment we prepared the water resources sections of EIR for NEPA/CEQA for a 0.5 acre auxiliary pumping plant. This included a detailed HEC-RAS hydraulic analysis from scratch, Hydrology, and water quality.

If you would like to learn more about Watearth and our services, please visit our website. We are happy to discuss your CEQA/NEPA project needs.

The Urban Heat Island Effect

Well over 140 million acres of America’s forests are located in urban areas. While many of us encounter trees within our cities and towns daily without a second thought, perhaps we should consider the implications of a sidewalk or other public space without trees.

As we see significant changes in climate and temperatures rapidly increasing over time – the 10 warmest years on record have all occurred over the last 16 years – planting trees is an effective way to combat these issues and provide a valuable resource: shade. It’s time to start treating trees like infrastructure by providing adequate space for roots and selecting appropriate trees for water use, climate resiliency, shade. Trees should be considered as elements in road right-of-ways, parking lots, and as resources within urban areas.

Shade canopies are particularly necessary in highly developed areas, which are more likely to experience the urban heat island effect. Urban heat islands occur when cities replace natural shade covers with areas that absorb heat, such as pavement, buildings, and asphalt.

Urban heat islands have numerous concerning outcomes, including health issues for those living in the impacted areas, as well as increasing greenhouse gas emissions and energy usage. From heat stroke to increased use of air conditioning and electricity, not prioritizing green solutions will be detrimental to humankind. Looking ahead, we can see the benefits of prioritizing green solutions such as clean air and renewable energy.

example of heat island landscape with sidewalk and wall without shade

Stock image via Pexels.

In recent years, however, cities and constituents have taken a growing interest in climate change solutions, including investments in urban forestry. However, not all forests are created equal, and in many areas lower income persons of color are on their own island.

In Los Angeles, former redlined areas are 7.6% warmer than their wealthier neighbors, who take up the majority of the shade. However, in 2021, LA is looking for a more equitable approach to make improvements in impacted areas. The City of Los Angeles is seeking to plant 90,000 more trees in 2021, with a special emphasis in previously neglected areas; they are hoping to increase their canopy by over 50% in the next seven years.

view of the city of Los Angeles

Stock image of Los Angeles via Pexels.

If Los Angeles and other American cities can remain consistently dedicated to improvements in urban forestry and continue to grow these forests, the results will be immense in the era of global warming. Shaded areas can often be between 20-45F cooler than unshaded areas, leading to less energy consumption. Additionally, health will improve as several environmental factors do. With more trees planted, we will see a massive decrease in greenhouse gas emissions and reduced air pollution. Water quality will also improve as trees infiltrate more groundwater and reduce surface runoff.

Here at Watearth, we are proud to work on projects that make our cities sustainable for the future. We are working with the City of Houston within the communities of Gulfton and Kashmere Gardens to provide planning services on their sidewalks to limit flooding and surface run off. Additionally, in Los Angeles, Watearth has worked with the city in creating an Environmental Impact Report (EIR) for the city sidewalks, specifically addressing tree canopy cover, examining the water quality impacts, and developing mitigation plans. Furthermore, Watearth has worked with the Orange County Transportation Authority (OCTA) looking at ways shade-providing plants can create safer railway stops for people waiting for their ride.

OCTA urban heat island index - October 2020
OCTA urban heat island index – October 2020

If you would like to learn more about Watearth and our services, please visit our website. We are happy to discuss your sustainability or resiliency green infrastructure projects.

If you’d like to learn more about how you can help low canopy areas in Los Angeles, visit the City Plants website.

The New

Watearth has experienced growth in the last year, expanding significantly in disciplines like landscape architecture, civil engineering, modeling, urban planning, biology, planning, permitting, and GIS. Our team has come to know each other very well, seeing changing markets as an opportunity to support each other professionally. With the addition of numerous senior staff to provide leadership in the engineering and environmental sciences, we are prepared and pleased to be moving through 2021 with a strong, balanced backlog of exciting projects from across the nation.

We’re looking forward to supporting your projects this year and beyond.

Watearth is proud to release our updated website. The first major update of the decade, these changes aim to make accessing and understanding our skills easier for clients and teaming partners alike. See the new pages at