greenvalues.cnt.orgGreen Values Stormwater Management Calculator

close Home About Calculator Resources developed byAdvanced Settings close Rainfall Data Financial Costs Soil Type Rainfall Data Rainfall data is based on local information collected over years and months from nearby weather station(s) * . Annual Rainfall: 0 inches edit Rainy days per Year: 0 days edit Average Rainfall (on a Rainy Day): 0 inches edit Variation in Rainy Day Rainfall: 0 (+/-) inches edit Storm Rainfall: 0 inches edit Hide graph * Data Source: NOAA - Hourly Precipitation Data (HPD) Automated System Version 1 Beta Release, using data from 1/1/2000 through 8/29/2017. Financial Costs Conventional Development Costs Below are cost assumptions for conventional development used to compare against green infrastructure alternatives. If you know specific costs for a project you may change them below for a more accurate comparison. Area Construction Cost Annual Maintance Cost Typical Useful Life Flat Roof ? $ 4 per ft 2 | edit $ 0.14 /Year per ft 2 | edit 20 Years | edit Pitched Roof ? $ 4 per ft 2 | edit $ 0.14 /Year per ft 2 | edit 20 Years | edit Sidewalk ? $ 7.32 per ft 2 | edit $ 0.0193 /Year per ft 2 | edit 40 Years | edit Patio, pool deck, etc. ? $ 12.52 per ft 2 | edit $ 1 /Year per ft 2 | edit 25 Years | edit Parking Surface ? $ 3.05 per ft 2 | edit $ 0.93 /Year per ft 2 | edit 15 Years | edit Driveway ? $ 6 per ft 2 | edit $ 2.25 /Year per ft 2 | edit 20 Years | edit Pool, Water Features, etc. ? $ 72 per ft 2 | edit $ 7.65 /Year per ft 2 | edit 25 Years | edit Street ? $ 4.33 per ft 2 | edit $ 0.055 /Year per ft 2 | edit 35 Years | edit Lawn/Turf ? $ 0.7 per ft 2 | edit $ 0.12 /Year per ft 2 | edit 12.5 Years | edit Flower Bed/Garden ? $ 0.7 per ft 2 | edit $ 0.12 /Year per ft 2 | edit 12.5 Years | edit Vegetable Garden ? $ 0.7 per ft 2 | edit $ 0.12 /Year per ft 2 | edit 12.5 Years | edit Shrub and Bushes ? $ 0.7 per ft 2 | edit $ 0.12 /Year per ft 2 | edit 12.5 Years | edit Raised deck ? $ 15 per ft 2 | edit $ 1.5 /Year per ft 2 | edit 15 Years | edit Natural Open Area ? $ 0 per ft 2 | edit $ 0 /Year per ft 2 | edit 100 Years | edit Natural Wetlands ? $ 1.4 per ft 2 | edit $ 0.03 /Year per ft 2 | edit 20 Years | edit Natural Water ? $ 0 per ft 2 | edit $ 0 /Year per ft 2 | edit 100 Years | edit Finance Data Financial cost estimates are based on a net present value calculation which assumes a 3.1 % discount rate over a 30 year life-cycle for all green and conventional investments. Discount Rate: 3.1 % edit Life Cycle: 30 years edit Flooding Costs (disabled) Flooding cost a lot of money. Let us know how often it floods and how much that costs you. Flooding Costs(USD/$): Year between floods Budget (disabled) Below are cost assumptions for conventional development used to compare against green infrastructure alternatives. If you know specific costs for a project you may change them below for a more accurate comparison. In order to determine how much you can spend of this project enter and approximate budget, and if there are any incentives/subsidies from the state/county/municipality, estimate the amount that can be added to the total costs. Construction Budget (USD/$): Annual Maintenance Budget (USD/$): Construction Incentives (USD/$): Annual Maintenance Incentives (USD/$): Curve Numbers The curve numbers for the different land cover are displayed below, and can be changed. The highlighted values are used in runoff calculations, by changing the soil type a different set of curve number are used. Hydrologic Soil Groups: A B C D A B C D Impervious Area Lawn in good condition Flower Bed/Garden Open Shrub and Bushes Food Garden Raised Deck Wetlands Water Real Estate Benefit To facilitate modeling the benefits of Green Stormwater Infrastructure (GSI) were grouped the into a set of four types based on their characteristics, the percent increase in estimated real estate value for each of these groups (and trees) is shown below. For further information on how these values were derived read Green Stormwater Infrastructure Impact on Property Values by CNT and SB Friedman Development Advisors. Effect of GSI Installations on Home Sales Price Description First Installation Doubling the Area Each Additional BMPs Group 1 - Rain Gardens, Swales, Planters, Etc.: Incudes swales, planters, rain gardens, and bumpouts, which are distributed forms of GSI that are typically vegetated, smaller in scale, and designed for stormwater infiltration. 2.8% 0.38% 0.2% Rain Garden, Planter Boxes, Foundation/Perimeter Drain, Amended Soil, Bio-Swales, Urban Farming/Gardening, Raised Bed, Vegetation Filter Strip, Parking Lot Swales, Roadside Swales Group 2 - Wetland, Trenches, Basins: Iincludes wetlands, basins and trenches, which are larger-scale stormwater management forms typically designed for stormwater detention. Infiltration and storage trenches are included in this group, but trenches specifically designated as tree trenches were excluded, because the property value impact of trees is well documented, and we wanted to examine the impacts of other GSI types. 3.1% 0.23% 0.84% Naturalized Detention Basin, Native Vegetation Group 3 - Permeable Paving: Includes only pervious/permeable pavement, which is a hard surface that allows stormwater to infiltrate. 4.1% 0.45% 0.95% Permeable Patio, Permeable Parking, Permeable Sidewalks, Permeable Driveway, Permeable Paving, Permeable Streets Group 4 - Green Roof, Rain Barrel, Cistern, Etc.: Includes green roofs, cisterns and rain barrels which all reduce stormwater runoff. 0% 0% 0% Green Roof, Rain Barrel, Cistern, Drywell Group 5 - Trees: The property value impact of trees is well documented, and therefore not modeled, instead the benefit used here is from other sources (see page 21 in Green Values Strategy Guide .). 5% 5% 5% Trees close Cost Assumptions The following is a list of ranges for installation, annual maintenance costs and estimated lifespan for a . Included are the sources used to obtain these values. Note that the default costs/lifespan in the calculator are the medium values. Construction Costs Range Cost Source Low $ 0 / -Medium $ 0 / -High $ 0 / -Annual Maintenance Costs Range Cost Source Low $ 0 / -Medium $ 0 / -High $ 0 / -Component Lifespan Range Lifespan Source Short 0 yearsMedium 0 yearsLong 0 yearsclose Evaluate benefits of green infrastructure to prevent urban flooding. View Calculator Learn More Compare the performance, costs, and benefits of Green Infrastructure to conventional stormwater practices. This calculator allows you to define one or more properties and then evaluate what combination of Green Infrastructure Best Management Practices (BMPs) meet the necessary volume capacity capture goal in a cost-effective way. Site Information Green Improvements Advanced OptionsPaste into an email or . Reset ValuesStart from a template or design a custom scenario. Urban Home Small lot 6,075 ft 2 (135’ x 45’) a small house garage sidewalk yard get started » Apartment Medium lot 8,400 ft 2 (140’ x 60’) a building sidewalk patio very small yard get started » Suburban Large lot 24,000ft 2 (200’ x 120’) a large house garage driveway sidewalk yard get started » Commercial Large lot 50,000 ft 2 (250’ x 200’) a building parking lot driveway small amount of landscaping get started » Urban Park Area 6.8 Acres Area With a Park 3 Acre park Streets and sidewalks Residential buildings, lawns and landscaping get started » Community Garden Small lot 6,075 ft 2 (135’ x 45’) 5 100’ x 4’ Raised Beds Paved Sidewalks Staging Area Lawn Walkways get started » Urban Farm One Acre Lot .75 Acres Cultivated 2 Hoop houses Small tool shed Shipping Container Paved Staging Area Lawn Walkways get started » Urban School Grounds Large Urban Lot (375’ x 330’) School Building Auxilary Building Parking Lot Paved Play Area Playground Sidewalks etc. get started » Custom Scenario Customize: A single site Multiple sites A Large Area get started » Where do you plan to add green infrastructure? a single site Calculate the impact and benefits of green...