Sustainable Drainage Systems (SUDS)

Why This is Important

Capturing rain and using this valuable resource is becoming increasingly important. Very wasteful farming practices (particularly the meat industry) and population growth are major threats to our water security, which currently effects 4 billion people, or 2/3rds of humanity. Both underground water and surface sources such as rivers are quickly running dry thanks in large part to over-extraction for livestock production. Tree and forest loss further disrupts the water cycle both making it harder for water to penetrate the ground where it can refill aquifers, but also reducing cloud growth, which reduces precipitation.

Groundwater recharging can take thousands of years to occur naturally, but we are losing this precious water at a startling rate, with a growing number of communities approaching or passing Day Zero. Once a community is past Day Zero they have to spend a fortune shipping water from other locations, and many people (if they can) migrate to more stable communities or countries.

In addition to threatening the viability of communities and their economies, severe ground water depletion damages foundations, threatening important structures such as roads, homes, dams, and bridges.

From this we can conclude that combatting deforestation, and switching to agricultural activities that use less water should be the first step in water management, but this page covers the other side of the water security "coin".

Benefits of Sustainable Drainage Systems or SUDS

Good water management on one area helps to reduce flooding down hill. 

Flooding is occurring more frequently due to all of humanities impervious building materials such as roofs and roads, as well as our obsession with draining water as quickly as possible via drains and ditches. As rain intensity and quantities increase, areas which previously received moderate rain are being reduced to rubble as hard-paved roads are turned into deep, deadly rivers. -  https://weather.com/news/news/2021-07-15-europe-flooding-belgium-germany-rain 

Natural rainwater harvesting systems are low maintenance, great for storm water/flooding. The can reduce water-use in the landscape to help create beautiful, native spaces which support local flora and fauna. 

Susdrain.org

"demonstrates the impacts of urbanisation on a catchment by reducing its permeability and increasing surface water runoff. This reduces opportunities for water to be managed naturally with the potential for pollution and localised flooding when the piped systems cannot cope with rainfall."

Benefits & Functions of Sustainable Drainage Systems (SUDS)

Introduction

These water management designs can help reduce flooding, water pollution, sequester water into landscape to reduce the impact of droughts and protect property against fires while preserving biodiversity. 

SUD designs can incorporate existing drainage systems, swales, berms, sumps, reservoirs, dams, forebays, and work passively with emergency overflow points to delay drainage which further reduces the chances of properties being overwhelmed by increasingly extreme storms.

By using natural processes instead of pumps, communities do not become inundated due to power outages or malfunctioning pumps which has caused catastrophic flooding in places like Louisiana.

SUDS vs Land Subsidence

By maintaining moisture within communities instead of full drainage, SUD systems provide the benefit of protecting communities from land subsidence which modern drainage and water extractions have massively hastened over the last 100+ years. 

For example "In New Orleans, Wood’s pumps—and their successors—have funneled groundwater and organic matter out of the water table for more than 100 years, leaving the dried-out soil to crumble under the weight of the modern city. This has resulted in the fractured roads and potholes that punctuate streets throughout New Orleans—and has caused more than 50 percent of the city’s geographic area to sink below sea level, according to Campanella. In a typical summer downpour, neighborhoods that previously saw little to no water accumulation have begun to flood regularly. Despite widespread suspicion of the S&WB’s capacity to keep the pumps running, the larger issue remains: the system that fights to keep New Orleans dry is sinking the city at the same time." - https://www.hnoc.org/publications/first-draft/pumps-built-and-sank-city-new-orleans

Introduction to Innovative Stormwater Management a 4:49 min Video "UBC's Master of Land and Water Systems program introduces the emergence of innovative designs and approaches to urban stormwater management at three scales:

Video #1: Property Scale

Video #2: Neighbourhood Scale

Video #3: Watershed Scale

This series is useful for developers, students, real estate agents, homeowners, municipal/regional planners, managers and engineers.

Production made possible by The Learning Centre at the Faculty of Land and Food Systems."

Introduction to Innovative Stormwater Management a 4:49 minute video

Innovative Stormwater Management at the Property Scale
15:34 minute video

Innovative Stormwater Management at the Neighbourhood Scale 14:18 minute video

Innovative Stormwater Management at the Watershed Scale
10:11 minute video

Features for SUDS

SUDS complies of a variety of features depending on local land features, soil types, climate, and local needs. The features that make up one might not match that of another, or they may share a small number of features or they may share all but a few features. Some systems will need repairs or updates due to climate extremes, as well as maintenance and check after major events such as heavy rain storms to ensure blockages are removed and don't contribute to flooding during the next snow melt or major precipitation.

Increase Water Storage Capacity

"Increased drought can reduce the safe yield of reservoirs. To reduce this risk, increases in available storage can be made. Methods for accomplishing this may include raising a dam, practicing aquifer storage and recovery, removing accumulated sediment in reservoirs or lowering water intake elevation." - https://www.epa.gov/arc-x/climate-impacts-water-utilities#tab-3

Dams & Reservoirs 

These can provide energy, preserve drinking water. These can be vital for retaining water in drought-struck regions, however damming systems can break up and harm aquatic eco systems which endangers many species of fish and amphibians. They can also rob water from delicate ecosystems resulting in toxic salt lakes and desertification. These changes can in turn result in water shortages and loss of income for communities that relied on water that dams may hoard.

Forebay 

Forebay systems can be utilized in SUD and wetland systems to reduce siltation and pollution, while providing an easy way to perform maintenance on the system. A forebay can be natural or excavated and is specifically designed to slow down waters, allowing for gravity-powered separation of water from sediments which can otherwise damage ecosystems downstream.

Swales and Berms

These can work separately or in conjunction to slow water and redirect it through landscape where it can reduce local temperatures and heat island effects, reduce pollution and erosion, all while reducing the chance and impact of flooding down stream. When the water is slowed down and moved strategically across a property, that water feeds the soil slowly which sequesters water where roots can reach it, which reduces water needed for gardens and crops. Over time, these structures can also help water recharge ground water resources. 

Infrastructure for Aquifer Storage & Recovery

This can reduce surface water run off and downstream flooding. Recharging ground water also means salt water intrusion can be reduced along coastal areas, while guaranteeing safe ground water for future generations.

"Increasing the amount of groundwater storage available promotes recharge when surface water flows are in excess of demand, thus increasing climate resilience for seasonal or extended periods of drought, and taking advantage of seasonal variations in surface water runoff. Depending on whether natural or artificial aquifer recharge is employed, the required infrastructure may include percolation basins and injection wells." - https://www.epa.gov/arc-x/climate-impacts-water-utilities#tab-3

Multipurpose

Urban Pond Storm Water Storage

These systems can be used to save valuable urban space by storing water under parking areas. Exit drains, overflow systems for high-volume rain events, keep the system within detention pond guidelines. Options for infiltration including drainage holes at the base of the systems. A gravel base can improve infiltration. Pumps and controls can be added to the system for landscape use in around and on top of the UrbanPond, with it's parking facilities. Treatment technology can capture trash, sediment, and chemicals before the water is stored, making it safer for irrigation, detention, or infiltration.

Wetlands: Natural & Manmade

Wetlands are natural sponges and vital for the survival of a large percentage of species, especially migratory birds.

Wetland Filtration  4:35 minute video demonstrates how man-made wetland filtration systems can release water up through man-made wetland filters made from specialized equipment, buried in rock substrate and wetland plants. 

These systems slow water, while filtering it of sediment and pollutants. Suggested maintenance: lift filter lid and clean out sediment at least once a year depending on local needs. Video shows installation and finished, functional system.

Controlled Release 

Beaver Dam Analogs

These are small, temporary dams designed to mimic beaver dams with local plant matter. Some even encourage beavers to move in, from which point their can take over the work, saving money, water, and improving ecosystems. Thece can be build with some simple wooden posts (live posts from indiginous trees can sprout into trees instead of rotting over time like older/dead posts) and locally gathered sticks. A post pounder may be needed for larger projects, but some can and have been built by a single person.

Dams like these work best in groups. Begin with 1-3, watch how the water behaves, and then add more BDAs as needed. Some dams will last for a few months, and others may last for years, especially if a beaver chooses to maintain it. This is an expected part of the natural process.

Beavers

Click the Beaver button to learn more about how beavers can cheaply and efficiently help prevent flooding, sequester water, create habitats, reduce run off pollution, and even protect against major fires. The link also includes more information about how to build structures including BDAs and PALS to mimic beaver dams or even invite them to colonize an area that may have been too dangerous for them prior to waterway alterations.

Check Dams/Gully Plugs/Trincheras

These are small (usually rock) dams that catch silt and other pollutants which allows them to break down instead of creating dead zones down stream. Slowing the water flow protects inhabitants down stream, while also allowing water absorb back into the water table. In arid or semi-arid regions this can protect down stream communities from deadly floods and extreme erosion, as the diverted water building up in the water table can turn gullies and wadis (which are generally dry except from some extreme seasonal flooding) into gentle, year-round (or almost year-round) streams as natural springs begin to flow. This is an ancient technique that prevents erosion, boosts biodiversity, while quite quickly allowing the soils of degraded habitats and farm lands to rebuild.

These may last for years, decades, or centuries. Kattas, a similar system used in India may be built, and dismantled yearly, however these are lined (most recently with synthetic liners) to increase retention/absorption of their seasonal rains.

"Soil erosion is a challenge throughout the world. Soil erosion results in the loss of soil and loss of usable land. If left unmanaged erosion will result in gullies.  It is important to manage erosion in order to prevent the loss of valuable soil and to maintain the area of usable land. One technique for managing soil erosion and gullies is the construction of check dams. 

The check dams trap the sediment behind the check dam and slowly reclaim the land. This also helps to prevent downstream impacts. Eventually the land can be reused. There are different types of check dams depending on the severity of the gully and the rate of flow of the water e.g. simple vegetation barriers, to more hardy stone based check dams. This video demonstrates how to construct check dams in erosion channels or for gully reclamation."

This 3:34 minute video talks about the two main types of check dams, suggests a wider range of building materials, explains the order in which check dams should be built to avoid creating new problems as well as the need to incorporate terraces to manage erosion, and cautions the importance of maintenance over time.

Check Dam info in Hindi (5:50 minute video) Includes building recommendations and design demonstrations.

This 1:14 minute video demonstrates how water flow and silt is effected by the presence of a check dam. 

AR Sandbox: Water Harvesting Check Dams 

(6:07 minutes)

This video demonstrates how check dams can alter and regenerate ecosystems, bringing more plants, trees, shade, regenerating ground water and ground porosity, which can even help generate freshwater springs lower down hill from the check dams.

"Kattas are traditional check dams built by farmers in Kerala’s Kasaragod district using mud and granite, in December every year. The stored water is used to irrigate crops till the end of May. Farmers will demolish the dams before the onset of monsoon. The check dams also recharge the groundwater table and ensure water availability even during the peak summer months."

Gabions

These are wire cages filled with rocks, very similar in design and purpose to check dams/gully plugs/trincheras, but build to withstand stronger water flows. 

For coastal restoration gabions can be used to create oyster reefs.

Ponds 

These can range from regular ponds to rain ponds. A rain pond should be planted with species who can survive a wide range of moisture levels as these features may be dry for months without rain. During heavy rain periods, plants in the basin area of these ponds should be the type that can handle waterlogged conditions in case the ponds remain full for weeks or months at a time.

Click the Gardening/Landscaping button to lean more about different types of garden features including garden ponds and rain gardens.

Spillways 

This basically means an overflow point for a pond, swale, dam, reservoir, or whatever might need to have a controlled exit point when flooding maxes out storage capacity. Picking a spillway that diverts water away from roads and urban areas, gives designers an opportunity to direct the water to places that can both handle and maybe even benefit from the extra water. Forests, orchards, wetlands, lakes, and rivers could be among the destinations, or a series of spillways can be used to passively irrigate any number of spaces including farms, forests, and even deserts with water that people need diverted away from their homes and businesses.

Swales

Swales, Ponds, & Spillways in the Rain 2 2:43 min Video demonstrates how silt can be captured in different features such as the silt pond (at around :46 seconds into the video) before emptying into waterways. "See full swales and ponds spilling in a heavy rain." 

Litter Traps

Litter and other types of pollution negatively effect the health of humans and wildlife. Preventing these from entering waterways or removing them as quickly as possible reduces the risks they pose to all of us protects water quality. We can use devices, design, various techniques and materials for cleaning litter and other pollutants from our water. Some of these involve meshes that need to be replaced, or bubble barricades which can control where plastic moves without interfering with boats, ships, or wildlife. Simply allowing nature to do her thing can result in biological litter traps.

Click the Litter Trap button to learn about specific designs that can be used within watersheds and SUDS to reduce pollution. There's also a section about wetlands and planting for cleaner water, and links to resources to determine and find appropriate plants for your project.

Click the Plastic Clean Up button for techniques, designs, organizations to join or support, and for safety advice.

Rain Gardens

Public water gardens or one built near public areas such as roads may catch plastic and other types of pollution. Maintenance to ensure these are cleaned out is important, but plants in the garden will help neutralize chemical pollutants.

Water Garden

Click the Water Gardens button to learn more about these garden which can affect water quality and retention. 

Ocean-Friendly Gardens

Click the Ocean-Friendly Gardening button to learn how to make your landscapes "ocean friendly" so that any run off, will not contribute to any aquatic die-offs.

Wetlands

Wetlands can be natural or man-made. In some places people are working hard to undo human "upgrades" so that historical wetlands can return to their former duty of protecting communities, repairing the water cycle, and providing their many biological functions.

These wild spaces not only dissipate and capture pollution, but wetland plants have been specifically identified which are able to remove pollutants such as PFAS from soil and water.

Click the PFAS Cleanup button to learn which species have been identified as effective for removing PFAS from the environment.

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Resources & Tools

Water Pumping

The pumping of water takes a larger amount than many people realize. Pumping ground water for agricultural, industry, or public use, moving it between facilities, etc. all require energy since water is a fairly heavy substance.

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Organizations

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The goal of A2 is to help communities fight back. We do that by providing them organizing support, scientific and technical guidance, and better access to foundation and government funding. Most of all, our work consists of listening to our frontline leaders. Their experience, research, and solidarity guide everything we do, and offer a path toward environmental and social justice.

Supported by outstanding partner organizations with expertise in engineering, hydrology, public health, planning, and the law, A2 leaders have successfully halted developments in climate-vulnerable areas; implemented nature-based hazard mitigation strategies; organized home buyouts; and pushed for clean-ups at superfund sites, toxic landfills, and petrochemical plants.

We support everyone we can, but our special priority is people who have suffered the worst environmental impacts for the longest time; that usually means low-income, Black, Latinx, Native American and other underserved communities.

To learn about our policies, read our A 10-Point Platform on Climate Change."

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Grants & Funding

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National award schemes There are a number of key organisations offering grants and advice to community based projects e.g. 

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