Capture, Cultivate, Sustain We return storm water to the water table in a controlled manner while improving the environment, producing local food, creating jobs, providing economic returns to the residents and the developer, and offering a truly sustainable lifestyle choice. When it rains, it grows…food, nutrients, financial return
Capture, Cultivate, Sustain WHEN IT RAINS IT GROWS! Ventana Lakes offers a new vision for storm water management and Low Impact Development (LID) – STORM WATER as a RESOURCE to be CAPTURED for PRODUCTIVE use, not simply returned to the water table by improved Best Management Practices (BMP’s) and porous materials. The Ventana Lakes plan is organized around the WATER VAULT system; utilizing LID techniques for conducting, filtering, and storing rainfall which is then re-purposed for irrigating Bio Intensive farm operations. We return water to the ground by GROWING FOOD! Our Development Supported Agriculture program is based on a Metabolic Agronomic Model - optimizing crop yield and monetary revenue from every square foot. Commercial ‘Civic 1 ’ farms provide consistent, marketable garden produce for the development. We also offer homeowners the option to share-crop their back yard with ‘Steward Farm 2 ’. The Steward Farm program is optional for every homeowner. They pay for the system that captures rainwater to irrigate modular garden plots on their property. These plots are tended by farm service professionals who harvest the food, market the direct sales, and provide a reasonable annual financial return to the homeowner. The development provides the infrastructure for agriculture and real estate to exist with mutually beneficial results. Street and lot orientation are crucial design elements that allow for maximum sunlight for both farming and photovoltaic use. We’ve eliminated the zero-frontage loop road of the previous plan and further reduced costs with an efficient street layout - which also offers a greater lot yield! Agriculture, ‘AG’, Alleys provide discreet access for Steward Lot farmers. These AG Alleys are integrated with the overall trail network resulting in a recreational trail system.
Development Supported Agriculture 1 Development Supported Agriculture (DSA) integrates natural agriculture practices with land development best-practices, policy, and lasting financial viability. DSA makes food production an integral element in the community design, social network, and lasting value of the neighborhood. It is about re-thinking and re-defining how we use land and water and how and where we grow food. DSA utilizes a calorie based accounting model that plans for and projects regional caloric food needs. This includes modification of standards and guidelines in the community codes, regulations and HOA bylaws where necessary; as well as development of municipal districts that promote agriculture, food production, alternative energy sources, and other sustainable concepts. Our approach provides at least 35% of the dietary needs of the development AND continuing annual returns to the developer and/or HOA through direct sales of the food. (“Site Plan A” refers to the conventional site plan and 1188 dwelling units provided with contest materials)
Development Supported Agriculture 1 <ul><li>The design/approach promotes and supports the following policies and principles: </li></ul><ul><li>Locally Grown Food: Production of a significant portion (30 to 50%) of dietary requirements grown within or in the immediate surrounding area of the community </li></ul><ul><ul><li>Conserves and Promotes Natural Resources: Appropriate and efficient use of natural resources provides housing, transportation, recreation and fresh food through creative, harmonious land planning and landscape architecture for the community. This includes use of alternative energy sources as well as land and water. </li></ul></ul><ul><ul><li>Self Sufficiency: Provides a commercially viable opportunity for enhanced self- sufficiency for community residents, tenants, and guests. </li></ul></ul><ul><li>In a traditional subdivision, only a small percentage of the actual land area is taken up with buildings and roads…the rest is left to public and private outdoor space. This “space amenity” consumes water, labor and land - without providing economic return or contributing to essential human needs. </li></ul><ul><ul><li>DSA integrates agriculture and food with land development. </li></ul></ul><ul><ul><li>Utilizes best-practices and policy to develop sustainable communities. </li></ul></ul><ul><ul><li>Integrates food in community, social and recreational places. </li></ul></ul><ul><ul><li>A new vision for feeding ourselves and how we live and play. </li></ul></ul>
Proposed Land Use and Trails <ul><li>Land Use </li></ul>Walkability
Proposed Drainage Plan Water Vaults flanked and hidden by “Civic Farms”
Maintainability/Marketability/Public Acceptance By not endeavoring to use unconventional materials for paving, hardscape, and building technologies, we achieve the same or better stormwater management performance with conventional materials. This is not just another development… <ul><li>Lifestyle: Local food, higher nutrients, and sustainable living appeals to a wide demographic </li></ul><ul><li>Financially sustainable: initially for the developer and eventually the homeowners through greatly minimized HOA dues </li></ul><ul><li>From a developer’s point of view, this concept: </li></ul><ul><ul><li>Smoothes Revenue Curves and helps absorption </li></ul></ul><ul><ul><li>Can provide a return on infrastructure even before the sale of a single lot </li></ul></ul><ul><ul><li>Offers a profitable option for developers holding land and waiting for a better market </li></ul></ul>
Economic Model A combination of savings through efficient, front loaded street design with sustainable returns through repurposing stormwater to bio-intensive farming realizing sales up to $5.00 per sq ft 2 is the foundation of our improved economic model We begin with contest supplied Site Plan A (“conventional/traditional design”) as the basis to improve from. Site Plan A Loop Road (2) Bridges
Ag-Alleys Ag-Alleys provide a service path to all the steward lots. Back yards are connected to the alley visually and with gates. Nodes create spaces for gardening activities as well as providing a social gathering area for neighbors. Ag Alleys enhance the neighborhood lifestyle by providing vehicle free walkways to schools and commercial areas, increasing the marketability of the development. The permeable Ag Alley path with drainage system creates a completely integrated storm water plan that is unique to this type of development pattern.
Civic Farm (cont.) <ul><li>Civic Farm installation may be covered through traditional financing tools (Metropolitan District, TIF, etc.) as it is essentially a form of drainage infrastructure </li></ul><ul><li>Organic soil amendment essential for regional soil conditions; future amending through “green manure” system: crop rotation & recycling old growth back to soil </li></ul><ul><li>Maintenance/”Farming Contract” to be held by district or HOA </li></ul><ul><li>Generates 2-3 professional farming jobs, bio-intensive/all natural methods </li></ul><ul><li>Assume additional seasonal paid labor at 2 FTE per 3 acres (50 plus additional 6 for steward lots) </li></ul><ul><li>Direct sales will range between $1.00-2.00 per sq ft (average of $1.50 used in this proforma.) Price is reachable due to bio-intensive farming techniques (more production per sq ft) and selling direct to restaurants, schools, institutions, and markets (eliminating nearly all traditional food chain middle-men and transportation costs) </li></ul><ul><li>Annual returns may be used to offset HOA dues: Example NET = $1900/year per homeowner </li></ul>
Steward Lots All homeowners may buy the cistern system with their lot, an approximately additional $30-50 per month amortized with their mortgage. Optionally, they may participate in the Steward Lot Farm system with raised beds and realize full recovery of their cistern investment in 4 years. Farm maintenance is provided through the general development farm contract; sales price per sq ft is higher than Civic Farm due to higher intensity farming; 10% sales charged to homeowner to be part of direct sales program. Assumed 50% of homeowners will participate in the Steward Farm System
Economic Comparison <ul><li>For purposes of example, we have assumed an accelerated absorption rate of 4 years, 25% of total lots each year. </li></ul><ul><li>“ Traditional Infrastructure” means wet/dry utilities and grading. Assume equal costs for each development. </li></ul><ul><li>“ Drainage” costs are considered a wash between each development. </li></ul><ul><li>Civic Ag revenue continues on past last lot sale (yrs 5+) </li></ul>
LID Model/Applications <ul><ul><li>Cisterns: (2-250 CF) are proposed for each residential home to collect roof runoff directly. (Use an average of 1670 sf roof area for each home, 1-inch of rainfall generates 139 cf of runoff. The provided storage therefore can handle a 3.6-inch storm event). </li></ul></ul><ul><ul><li>Use the harvested rain for drip irrigation for farming steward lots. Assuming an average of 600 sf of farming area, which equates to 200 cf of irrigation volume needed per month (at 1” per week). Provided cisterns therefore can store sufficient rainfall for 2.5 months of farming. </li></ul></ul><ul><ul><li>Other additional LID measures such as level spreaders and rip-rap aprons with plunge pools at the storm drainage outlets are proposed to convert the concentrated discharge into sheet flow and help reduce the energy and velocity. </li></ul></ul><ul><ul><li>BMP wet detention ponds that provide: </li></ul></ul><ul><ul><ul><li>Permanent pool volume that meets state and local requirements </li></ul></ul></ul><ul><ul><ul><li>Water quality treatment for the first inch of runoff. ( The provided WQ volume in BMP ponds accounts for the house roof area again, which will be captured by the cisterns. This provides WQ treatment if the cisterns are full.) </li></ul></ul></ul><ul><ul><ul><li>Irrigation for civic farming. ( Holds equivalent volume of 1-month supply, based on the assumption of 1” per week for 1-ac of farming, with a 45-week growing season.) </li></ul></ul></ul>This design concept utilizes a combination of LID and best management storm water practices (BMP) to control and treat the first inch of runoff and control the increase in storm water runoff volume associated with the post-construction conditions. The site design techniques, strategies, and practices seek to store, infiltrate, evaporate, retain, and detain runoff, thereby limiting the increase in pollutant loads caused by the development. The following infrastructure and practices are proposed:
LID Model/Applications Drainage areas and hydraulic path feeding into the study conveyance system were analyzed. With this information, hydraulic length, time of concentration (TOC), and basin slope were determined for the pre-developed and post-developed conditions. The composite curve number (CN) was calculated based on the hydrologic soil types and groups from the U.S. Department of Agriculture, and available geotechnical report. Composite CN used less restrictive hydrologic soil groups to be consistent with the Competition’s assumption. The total impervious area of the development was estimated. The water quality volume of the first inch of rainfall was quantified using the Schueler simple method. The irrigation volume was also quantified. Irrigation storage in BMP wet detention ponds and individual home rain barrels were determined based on available rainfall data from the National Weather Service for Houston, TX for the past 5 years. Hydraflow Hydrograph models were developed to determine the peak flows for the 5, 10, and 100-yr storm events using SCS Unit Hydrograph with 24-hour storm distribution and the Harris County rainfall precipitation data. Storm water sewer systems, LID and BMP designs are based on ‘Stormwater Quality Management Guidance Manual’ for City of Houston and Harris County, Texas, ‘Minimum Design Criteria for Implementation of Certain BMPs’ of Harris County, ‘Infrastructure Design Manual’ of City of Houston Department of Public Works and Engineering, and the ‘Hydraulic Design Manual’ of Texas DOT. Limited topographic data and overall existing condition analysis were supplied by the Competition. Since the suburban development is only a part of the overall post-development, which includes a separate portion for the school and outparcels for future commercial developments, ‘extrapolating’ the storm water values for the isolated studied ‘pod’, then applying it for the overall site could be misrepresentative, particularly because of the nature of their different developments and varied respective discharging points and time of concentration.
LID Model/Applications Stormwater management facilities such as the BMP wet detention pond proposed will provide up to 85% total suspended solids (TSS) removal, 25% total nitrogen, and 40% phosphorus. Its regulatory credits vary slightly among different jurisdictions but are accepted in Houston, Texas, as well as most jurisdictions nationwide. The proposed BMP facilities are wet detention ponds. The BMP facility is designed to control and treat the first inch of runoff volume, with a drawn-down rate between a 24-hr to 48-hr period, and control the peak discharge rates for 5-yr 10-yr, and 100-yr, 24-hr storm events so that the total discharge in the post-development condition would be equal to or less than that of the pre-development condition.
LID Model/Applications So that the comparisons can be more precise, separate pre-development and post development analyses for the two watershed areas (pods) were studied. Pod A totals 120 ac. and consists of 60-ft. Pod B totals 70 ac. and consists of 50-ft lots.
Reduction of Storm Water Runoff Though the drainage system is planned/sized/quantified to handle all roof runoff if no cistern is used, volume reduction will be achieved through roof runoff captured in cisterns and repurposed through drip irrigation for raised bed farming in individual lots, as optioned by the homeowner. Run-off from other impervious areas on the site (i.e. drives, streets, etc.) is captured for use by the civic-farms in wet detention ponds. This irrigation storage is in addition to the permanent pool and water quality / detention volumes. A month of water irrigation supply for the total civic-farm area is provided. This additional layer of retention for the site further reduces the total runoff volume leaving the site. The irrigation volume is considered as part of the permanent pool volume of the pond. It fluctuates based on the irrigation needs but will remain in the pond indefinitely. The outlet control measures are placed at the irrigation water surface elevation (IWS), not at the permanent water surface elevation (PWS). If the irrigation volume is used before the next storm event comes, the available irrigation storage will help to retain part of that next storm event runoff volume and will reduce the volume leaving the site. Note: 10’ safety/aquatic shelf is at the IWS. Vegetation will be selected which can tolerate the ‘dry’ time when irrigation volume is low, and the submerged condition from larger storms. This is both a water quality and an aesthetic measure intended to screen the unvegetated banks where water fluctuation is frequent.
Design Goals Conserve natural resources that provide natural functions associated with controlling/filtering storm water Conservation by stormwater reuse onsite is a primary design element focusing on decentralizing the stormwater retention / detention and lengthening time of concentration by allowing for reuse of stormwater at the individual lots and development farms. Minimize/eliminate use of potable water resources for irrigation and where practical, provide for reuse of rainwater Houston, Texas and surrounding towns are located in an environment that is unpredictable and requires flexibility to climatic conditions. The average temperature provides diverse opportunities in crop types and growing seasons. The average rainfall of +/- 54 inches for the Houston area creates opportunity for onsite water collection to reuse for crop irrigation and eliminating the need of potable water resources. This design offers flexibility to supplement with limited use of well water resources during times of severe drought to maintain crops.
Design Goals Minimize/disconnect impervious surfaces, lengthen time of concentration and promote bio-filtration of runoff to improve quality of storm water leaving site By taking advantage of the existing collector roads surrounding the site, the internal road system can incorporate a more pedestrian oriented road system. A pedestrian oriented road system will reduce traffic speeds and reduce pavement widths, characteristic of collector roads. The proposed design uses a hierarchy of streets; however it prevents any one street from being over-burdened with traffic. This design accomplishes a pedestrian oriented street system by removing the original loop road and incorporating housing on both sides of streets where possible. The benefits of providing double loaded streets are an increase in pedestrian safety, more efficient lot yield, and a reduction in pavement widths. In addition to incorporating double loaded streets, this design also reduces pavement and infrastructure by using shorter block lengths and cul-de-sacs, without clustering or compromising connectivity. The increase in lot yield and reduction in pavement widths and lengths provides the developer the opportunity to invest the profit back into the development, for additional site features and to enhance the quality and longevity of the project. The bio-swales retaining and detaining the water as well as forebays along the water vaults allow for filtration of stormwater before reuse for irrigation and release offsite.
Design Goals Use decentralized, small-scale landscape features and LID IMP to work as a system to: <ul><li>Reduce amount of runoff by mimicking natural hydrologic function of the site and matching pre-development hydrology </li></ul><ul><ul><li>Runoff from lots (with and without cisterns), development site, adjacent Katy ISD, and adjacent commercial sites is transported by sheetflow, ditch, and reduced pipe to a series of onsite open retention swales to reuse for onsite irrigation of farms and amenities where it is detained and released at the pre-development rate. </li></ul></ul><ul><li>Minimize the use of and/or reduce pipe size and other centralized control and treatment infrastructure </li></ul><ul><ul><li>Incorporating integrated management practices into the design for Ventana Lakes was essential. The primary focus for IMP was onsite stormwater reuse. This was achieved by focusing on reducing the infrastructure needed for the site. By reducing pavement widths and lengths, the amount of storm drainage pipe required can been reduced, allowing a reduction of pipe size and depths. </li></ul></ul>
Design Goals Lower total cost of development compared to traditional infrastructure design The result of this design concept is a forward thinking, environmentally conscious and cost saving development. Benefits of this concept include additional (32) lots, reduction in infrastructure costs due to design layout, greater marketability to homebuyers because of the lifestyle and financial options available to them at a marketable price point.
Sources 1 All principles and tables under Development Supported Agriculture heading, “Civic” and “Steward” terminology, and proforma calculations/unit values used with permission. All Rights Reserved 2 “Mini Farming for Self Sufficiency”, Brett L. Markham, 2006 “ Pumping Water for Irrigation Using Solar Energy”; Fact sht EES-63 “ Solar (Photovoltaic) Water Pumping”; The Schumacher Centre for Technology & Development Texas Metal Cisterns, 3351 S. Old Bastrop Hwy., San Marcos, TX 78666