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The modern water harvesting movement is part of a broader change, or paradigm shift, in how water is treated on sites. And that is the shift from viewing water as a problem to seeing it as a resource. As indicated in this slide, water leaving a building is channeled through the landscape on onto a nearby street. As this occurs the water often increases in velocity, picks up sediments and pollutants, and contributes to downstream flows and erosion. And importantly, it is not allowed to infiltrate within the site and become a resource for plants and other purposes. 2
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Cochise Hall Water Harvesting / Storm water Management - Class Project 2008 4
Storm water retention / detention basin East of the UA Nursing Building. A larger scale implementation than the example in the previous slide, but conceptually it is the same water below an outlet level, or weir, is being retained on-site. This water either infiltrates into the soil, evaporates, or is used by plants. 5
Rain water is the primary source of water we ll discuss in this class. Below are a few additional types of water that can be harvested (although not an exhaustive list of all types). 6
It is important to understand that rain comes in different size events (.25, 1, 2 etc.), and depending on the area of land the rain falls on (the watershed) in combination with the size of event, different approaches are needed to manage the runoff flows. The three photos above show structures designed to manage overflow in a combination of different size events and watershed sizes. Controlling, or metering, flow between catchments is important for managing downstream flooding, preventing erosion, and holding water in catchments where infiltration is desired. 7
Gray water is water that has been used for various purposes, resulting in a level of water quality that not potable but is benign enough to be used in landscapes. Toilet water is considered black water, not gray water. Drinking fountains, kitchen sinks, laundry water are commonly considered gray water. In the photo above, gray water from a laundry facility empties through a small black pipe into a catchment planted with citrus trees. This basin is designed to also accept rainwater. Combining rain water with gray water is a good design pattern because the pure rain water helps dilute particulates and chemicals in the gray water. A benefit of gray water for the type of application shown above is that it normally is created regularly/daily, so for plants that require regular water (such as citrus trees), gray water can be more useful than only passively collected rain, water which only is available when it rains (and a period after that while it is stored in the soil). 8
Condensation forms in association with air conditioning equipment/infrastructure. This water can be captured and placed into landscape catchments or tanks. 9
A number of industrial processes produce water that can be captured and used rather than disposed of through a sewer. In the photo above, water from the draining of a swimming pool was captured in the truck and used to water neighborhood trees. 10
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The primary use of harvested water we ll discuss is for watering landscape plants. The above diagrams show a native plant palette and landscape plan for a portion of the UA Visitor Center. 12
There are many different professional specializations involving water, and associated challenges or concerns. Water harvesting projects are a way to create benefits that address all of these topics to a certain degree. This may occur through efforts that can be simple and easy to start on a small scale, contributing to the appeal of water harvesting. With water harvesting we re trying to create environments that have more of the living or green qualities as shown on the right, but without the large amount of imported recourses. The manufactured landscape on the right would appear more like the barren landscape on the left if the flow of imported resources were stopped.
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Example of storm water mitigation, and possible aquifer recharge. 15
Water for this fountain is harvested in the low areas under the Warren Ave. underpass and stored in a tank on the north side of Speedway Blvd. This water is used in the fountain as long as it lasts, and then City water is used. 16
In the summer, a large amount of water is consumed by evaporation and blowdown in association with cooling. 17
This Tucson family harvests water from their roof, stores it in an underground tank, and treats it to potable drinking standards in their garage. Provides for all indoor use and also supplies a small pool. 18
All water used on the Kitt Peak telescope site is harvested rain water. Catchment shown above. Also have a treatment building and several 500K storage tanks. 19
The next series of slides will review a range of different types of water harvesting projects. 20
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Example project context: Private, low density residential, DIY retrofits, using rain for landscapes 23
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Street-edge basin supplied from street runoff through a curb-cut. 25
Rincon Heights street edge water harvesting demonstration project, 9 th and 10 th streets from Campbell to Park Ave. 26
Large scale redevelopment very well integrated design. Curb cuts evenly spaced, trees in between curb cuts, etc. Highpoint Neighborhood in West Seattle. 27
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Large commercial development at SW corner of Tangerine and Oracle. Water harvested from commercial building roof, stored in tank, used for landscape irrigation. 29
Simple passive water harvesting, roof drains into shallow, broad basins at an office complex in Tucson. 30
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Kino Environmental Restoration Project in Tucson. Storm water stored in deep pond used to irrigate turf. 32
A park-line environment created with hybrid water harvesting / storm water basins throughout. 33
Check dams allow linear basin to be segmented into ponds that allow water to slow and infiltrate rather than the water all flowing to the low point (in the absence of check dams). 34
Subtle changes in road design make a difference. Curbs flush with pavement, sloped into median which is slightly recessed and planted with native plants. 35
Structured approach to street-edge water harvesting in a very pedestrian-heavy area, north side of Reid Park in Tucsn. Features structural soil in concrete structures and under walkways to increase water and air flow to root zones, thereby allowing for wider and better root growth. 36
Evolution of street curb cuts Sixth street near downtown Tucson. Series of curb cuts designed for an arterial road direct street storm water into landscaped bases. Recycled concrete used for erosion protection and to meter flow between basin segments. 37
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Basins at AME building on the UA campus. Phot - Prabjit Verdee 39
Cisterns at the UA Visitor Center. 40
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ENR2 building on the UA campus. From concept diagram to rendering to technical plan for managing water on the site. 42
ENR2 has a large, underground storm water harvesting tank. The tank is a Contech steel reinforced polyethylene structure. It is 8 in diameter, 140 in length with a volume of 52,600 gallons +/-. The intent was to capture stormwater runoff for irrigation reuse, and assist in achieving LEED platinum status for the project. The tank will capture runoff from all roof drains, from within the canyon, and around the perimeter of the site. The tank was delivered in three sections, placed in the excavation, welded together, filled with water, and then backfilled with a slurry mixture. The attached pictures provide an idea of the installation process. 43
Tucson site of the Nature Conservancy, developed as a water harvesting demonstration site. Tours available. Iconic cistern placed in a location and designed to draw attention to itself. Features a water level gauge and rain chain that celebrates the rain with the tank overflows. 44
Left Police Station, Alvernon/Broadway in Tucson Right - NW YMCA Conveying beauty, sense of place, natural process, etc., by making water visible 45
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Must consider intensity of use in various environments, and how water harvesting infiltration can be accomplished in each. 47
Example of how infiltration was achieved in a very high-pedestrian environment. Water directed to an green space that creates an amenity and infiltrates water, but keeps large pedestrian flows on hard surfaces so that the infiltration surfaces and related vegetation don t get trampled. 48
Apartment building on west side of Tucson. Architectural form of a swale conveys water through the landscape, allowing for some infiltration before outletting. 49
Sculptures that becomes fountains when it rains. 50
Map of UA water-related sites. 51
Water harvesting principles from class textbook (Lanscaster). 52
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