Blue Roof
Table of Contents
Introduction
"A blue roof is a roof of a building that is designed explicitly to provide initial temporary water storage and then gradual release of stored water, typically rainfall. Blue roofs are constructed on flat or low sloped roofs in urban communities where flooding is a risk due to a lack of permeable surfaces for water to infiltrate, or seep back into the ground.
Water is stored in blue roof systems until it either evaporates or is released downstream after the storm event has passed.[1] Blue roofs that are used for temporary rooftop storage can be classified as "active" or "passive" depending on the types of control devices used to regulate drainage of water from the roof.[2] Blue roofs can provide a number of benefits depending on design. These benefits include temporary storage of rainfall to mitigate runoff impacts, storage for reuse such as irrigation or cooling water makeup, or recreational opportunities." - Wikipedia: Blue Roof
Benefits of Small / Local Solutions
According to a South African case study, "Small, local solutions can crack water crises"
Before you get started on any project, always be careful to check your local legal codes and policies. Some types of water harvesting are forbidden in certain places for a variety of reasons.
Some water capturing methods may pose a hazard if they overflowed or broke, so proper site investigation and materials should be used.
North America
You may also be interested in reading about:
Learn about which activities use the most water, to develope a plan on curring your own water footprint. In many cases consuming less will have a greater impact than harvesting water, though water collection may be your first step in your water conservation journey.
Benefits of Blue Roofs
This takes every drop of water that lands on a rooftop, directing it to a gutter which can collect it in rain barrels or cisterns for later use. Any overflow can be directed towards water harvesting landscape features such as water gardens, however these features should be at least 3.33 meters (10ft) from any structures and their foundations.
"In the past, blue roofs were conceived as storage tanks for rainwater harvesting. Today, they form part of SuDS best practice and are designed to facilitate controlled attenuation following heavy rainfall or storms. Blue roofs are suitable for a wide range of building types from domestic to commercial. They place storm water attenuation within the building footprint, making them ideal for urban environments where ground space is limited. Blue roofs can be situated above the waterproofing membrane in a warm roof system or above the water flow-reducing layer in an inverted application, at both roof and podium levels. There is a case to be made that green roofs are a form of blue roof, because they hold water and control run-off; but green roofs cannot do this in a truly controlled way such that the attenuation capacity can be relied upon to be available for a statistically derived storm event. Specifiers may like to consider the hybrid blue/green roof, which combines the aesthetic and ecological benefits of a green roof, with the high-performance water-attenuating properties of a blue roof." - Architecture Today: Roofing in Detail Blue Roofs Best Practice
How safe is roof-water to drink?
Rainwater Research in Australia & New Zealand This research shares a lot of information about the basics of how beneficial increased use of collected rain water would help fulfill our water needs, and that as long as the suggested safety measures are followed "You are more likely to contract illness from drinking mains water compared to rainwater." then it explains the main sources of contamination and disease including lack of proper maintenance. "In South Australia, 42% of residents mostly drink rainwater in preference to mains water without any apparent effect on the incidence of gastrointestinal illness (Heyworth et al. 1998)."
Life Expectancy: 10-25 years, but some components made from certain materials can last 50-100 years. Green Roofs are expected to survive for 40-50 years.
Pro: Captures precipitation that might have otherwise contributed to run off and flooding.
Con: Relies on precipitation, meaning it may be unreliable in drier climates.
Solution: People who receive seasonal rain should build ample storage space to help capture as much rain as possible, ensuring more water will be saved for later in the year. They may also want to consider other options such as a well with recharging infrastructure, a grey water system, etc.
Fuel Types: Water Cycle + Gravity
Complimentary Options
Green Roofs
A green roof is a roof with plants, and may consist of grasses, succulents, and even wild flowers. They can look wild and rugged, which is perfect for wildlife, while requiring little maintenance.
Roof Gardens
These gardens can consist of patios with flower beds or potted plants, or can conist entirely of planted space. They can be used to produce fruit, vegetables, and herbs, used to entertain, or even include small trees.
Hydropanels
These can be set on the ground or on rooftops.
Additional Equipment
Rain Barrels/Butts & Cisterns
Life Expectancy: 20 years.
Pro: Safely stores rain or grey water for later use.
Con: An turn into a breeding ground for mosquitoes, or be contaminated with dead animals that can fall/get trapped inside. I've found dead frogs who might have hatched but not been able to get out. Dead leaves can build up, leaching tannins into the water.
Solution: Install fixtures that will help keep wildlife and leaves out of the system. Make sure to clean these to prevent plugging and backups. Empty and clean out the container periodically.
Fuel Types: Water Cycle + Gravity
Alternative At-Home Water Harvesting Options
Water Recycling
Grey Water
Simple Greywater Systems For Your Home "A greywater system is used to take water that has already been used from places like your laundry, shower and sink and divert it to use in another purpose like watering gardens or landscaping instead of flushing it down into the sewer. Greywater is different from blackwater (aka sewage) because while it may have some residuals like dirt, hair, grease, etc from it’s first use, they aren’t toxic to the environment and the water can be reused in some applications." When using a grey water system for irrigation, it is important to be very careful in choosing "bath soaps, used homemade shampoos and biodegradable dish soap so as not to damage the soil, plants or watershed." Link talks about legal issues, installation costs, and design elements such as filters.
Toilet to Tap Water Recycling
Toilets can use grey water, function without water, or be a source of water depending on the type you choose, and the infrastructure around it.
Tools & Resources
Landscaping Know-How
This may give ideas for how to capture and redirect water on the land, which can integrate well with rooftop water harvesting.
Greener LAND "This tool helps you decide which landscape interventions are best suited towards landscape restoration for the landscape you operate in. Start by selecting the characteristics of your landscape on your left."
Organizations
International
WASH "curriculum has been developed and integrated in schools (Shikshaniketan, Residential Bridge Schools & Solar Bridge Schools) run by Barefoot College International. Every year, new activities and methods are included which makes learning interactive. Area covered include Water, Sanitation, Health, Hygiene and Environment."
Africa
WASH "curriculum has been developed and integrated in schools (Shikshaniketan, Residential Bridge Schools & Solar Bridge Schools) run by Barefoot College International. Every year, new activities and methods are included which makes learning interactive. Area covered include Water, Sanitation, Health, Hygiene and Environment."
Asia
India
Rainwater Project "So far, Rainwater Project has restored six historic water structures in Telangana — Kokapet Well, Goshala Well, Kondapur Well, Gachibowli, Baaram Bavi and Bansilalpet Well." "It also offers rainwater harvesting and water conservation consultancy services for individual homes, gated communities, farms, resorts, schools and other institutions." - Kalpana Ramesh: The architect leading restoration of Telangana’s historic stepwells
WASH "curriculum has been developed and integrated in schools (Shikshaniketan, Residential Bridge Schools & Solar Bridge Schools) run by Barefoot College International. Every year, new activities and methods are included which makes learning interactive. Area covered include Water, Sanitation, Health, Hygiene and Environment."
Europe
UK
North America
WASH "curriculum has been developed and integrated in schools (Shikshaniketan, Residential Bridge Schools & Solar Bridge Schools) run by Barefoot College International. Every year, new activities and methods are included which makes learning interactive. Area covered include Water, Sanitation, Health, Hygiene and Environment."
Mexico
Isla Urbana "has designed an environmentally, socially, and economically sustainable rainwater harvesting system that collects and cleans rainwater for households, schools, and health clinics.
The system is inexpensive, easy to install, and provides individual residences with about 40% of their annual water supply. If implemented on a large scale throughout Mexico City, this simple technology could provide 30% of the city’s water and help give a sustainable water source to the 12 million Mexicans who lack access to clean water."
USA
American Rainwater Catchment Systems Association (ARCSA). Offers trainings and accreditation for rainwater installers. They also have a comprehensive list of rainwater resources here.
DigDeep "Water-storage barrels with pumps or household rainwater catchment solutions to reduce the reliance on single-use bottled drinking water in Chichiltah, NM, supported by community education around plastic pollution and sustainable alternatives to bottled water."
Watershed Management Group. (Tucson and Phoenix, Arizona). Offers classes, a “water harvesting coop” and more.
Oceana
WASH "curriculum has been developed and integrated in schools (Shikshaniketan, Residential Bridge Schools & Solar Bridge Schools) run by Barefoot College International. Every year, new activities and methods are included which makes learning interactive. Area covered include Water, Sanitation, Health, Hygiene and Environment."
South America
WASH "curriculum has been developed and integrated in schools (Shikshaniketan, Residential Bridge Schools & Solar Bridge Schools) run by Barefoot College International. Every year, new activities and methods are included which makes learning interactive. Area covered include Water, Sanitation, Health, Hygiene and Environment."
Maps
North America
USA
Stormwater Management and Restoration Tracking (SMART) Tool (Interactive) Tool tracks storm water management practices in the Chesapeake Bay Watershed which spans, Delaware, New York, Pennsylvania, Virginia, and West Virginia
Grants & Funding
Oceana
Australia
Western Australia
The Sustainability Grants Program (in the City of Cockburn) "offers funding for projects related to six sustainability themes. Open to small businesses, schools, not-for-profits, and collective households, successful applicants can receive up to $4,000 for their project."