TRANSITioning the WATERSHED Balance systems to
CAPTURE surface runoff HARVEST rainfall REUSE adjacent greywaters
[Layering sustainable WATER management] for landscapes within Places which
experience population growth soon promote sustainable lifestyle
Water is a vital and misunderstood resource in arid urban environments. Climate change, rapid urbanization and likely future drought, place the Phoenix metropolitan area at risk of water scarcity. Arid urban landscapes are particularly vulnerable. They depend on supplemental irrigation to provide robust ecosystem services. In order to ensure those ecosystem services, we must design the water budget for urban landscapes to be independent and resilient. With the expected urbanization that accompanies transit-oriented development, there is opportunity to test the layering of multiple water management systems for creating urban landscapes resilient to water scarce futures.
Colorado River
Arizona
Verde River Watershed
Salt River Watershed Phoenix AMA
In the past century a series of water management systems developed which enable urban settlement to occur in the arid southwest. See figure 1. The redundancy of layered systems has removed the population from the challenges of water scarcity. The systems are nearing capacity and require a future of less water demand. It is difficult to change or shift the culture of water use that has developed in the Phoenix metropolitan region. As Paul Goldberger described fifteen years ago, our relationship to water in the west is one of expectation:
figure 2. Colorado River Basin Water Supply and Demand Study
U.S. Department of the Interior, Bureau of Reclamation
”Water is critical, but once it is provided - as it has to be or Phoenix could not exsist - but once it is provided it does not bring and answer to what this city should become. It is a precondition to an answer. The politics of water, as all of you know, are essential, but they are not, in themselves, an answer. It only buys you entry into the next level of questions.” -Paul Goldberger Desert Cities: Water Politics and Design Dinner Lecture, February 19,1999
Mesa
CAP canal
Colorado River water harvested through Central Arizona Project Salt and Verde Valley watersheds captured by Salt River Project Aquifers within Phoenix Active Management Area, used and reused
Productivity
prolonged
DROUGHT
$$ HARDSHIP
decreases available water
increase HEAT A index AT
figure 3. Urban landscapes at risk during water scarcity
Many techniques capture and infiltrate stormwater. Green Infrastructure is often used to describe a network of decentralized stormwater management practices. “The collection of rain without an artifical inducement.” - (2012) Kinkade. Design with Water
The intent is to concentrate runoff and collect it in a basin or cistern to be stored for future use. The water is eventually delivered through an irrigation system. Project: Ten Eyck Landscape Architects Inc. Underwood Family Sonoran Landscape Laboratory
ALSA.ORG
‘R’ yield %supply
KL
ETo irrigation system inefficiency
Project: Kevin Robert Perry, ASLA SW 12th Anvenue Green Street Project
HARVEST REUSE
DEMAND
The directional collection of rainfall into defined permeable regions for infiltration
ALSA.ORG
‘H’ yield %supply
(The Value of Green Infrastrcture, Center for Neighborhood Technology, 2010) and (City of Melbourne, Urban Forest Strategy, 2012)
As we prepare to transition to a less abundant water future, we must find ways to communicate the relationship between water and the ecosystem services it enables. It is a difficult to balance multiple systems to promote resilient ecosystem services- but that balance must be on display to engage the public in a discourse about water futures in an arid urban environment.
CAPTURE
‘C’ yield %supply
figure 4. Ecosystem services of urban trees compiled from
plant coefficient
evaporation transpiration
WATER
less precipitation
Urban landscapes are particularly at risk during water scaricity. See figue 3. More than half of our water demand in the Phoenix metropolitan area goes towards irrigating landscapes. The arid southwest does not recieve enough annual rainfall to sustain vegetation in the challenging environment of urban cities. In addition to capturing rainfall to water urban plants, we must also find other sources to supplement the water demand of healthy, vibrant landscapes. Within the urban watershed there are also three potential sources of water the may be captured, harvested, and reused to sustain urban landscapes. We are just being to quantify the benefits of green infrastructure within our cities. See figure 4.
runoff
figure 1. 3 Sources of water in Central Arizona
In another fifteen years, water will no longer be a precondition. See figure 2. It will be more central to our daily choices. Our relationship to water must be part of the answer of what our cities will become in water scarce futures.
Recirculating previously used water within the site
DELIVERED
percolation
How much water meets irrigation demand to ensure continued ecoservice benefits of landscapes in arid urban environments?
Greywaters: waste waters of previous use with varying degrees of contamination excludes waste water contaminated by human waste (blackwater)
Greywater systems are varied and complex.
context specific, numerous sources, increased investment, clearly defined goals
Project: Ten Eyck Landscape Architects Inc. Underwood Family Sonoran Landscape Laboratory
ALSA.ORG
Gilbert Rd / Main St - future Light Rail TOD
Mesa, Arizona
Non residential parcels likely to be redeveloped with the addition of Light Rail
Major ridges define urban watersheds Land Use Legend
University Drive
Light Rail Station expected completion 2018
Minor ridges contain and direct flows
Co
Gilbert Drive
Stapley Drive
Ranking and grading of parcels likely to be redeveloped.
Lindsay Road
Main Street
ns ol
ed at id l
na Ca
Surface flows within watershed, commercial properties function in isolation
Broadway Road
Development Opportunities within
WsTOD The transit oriented district surrounding the light rail station at Gilbert Rd and Main St in Mesa, AZ is likely to experience rapid redevelopment in anticipation of the new light rail station opening in 2018. Parcels were identified that will likely be redeveloped and the potential water supply and demand of these new landscapes were identified. The relation of each parcel to the adjacent watershed was considered when calculting possible supply and demand. This is method establishes the required resources necessary to determine if a balanced water system is possible. As the design refines, the numbers also refine.
Traditional TOD defined by 15 minute walkability
TOD defined by flows of water within 15 minute walkable watershed
Watershed Transit Oriented District (WsTOD)
8 guidelines of WsTOD design
Walkable Human Habitat
Showcase Water Components
Accommodate Plants
Diverse Plant Palette
Efficient Collection/ Delivery of Water
Sustainable Materiality
Relate Site Development Reveal Conveyance to Ecosystem Services
WsTOD guidelines are basic considerations to apply in the design of redeveloped parcels within the walking distance of transit hubs. Their intent is to streamline the efficiency of the layered water management systems while exposing the function of those systems to the diverse users passing through these transportation hubs.
Outcome/Benefit: Capturing, harvesting and reusing water available within a transit-oriented development district to meet irrigation needs of landscapes- ensuring continued ecosystem services benefit within arid urban environments.
LDE / MUD 593: Spring 2015 Applied MLA / MUD Project
Student: Mary Villarreal Instructor: Kenneth Brooks