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Guideline S.2: Site Water Quality and Efficiency

Intent

To restore the natural water cycle of Minnesota biomes in order to support natural hydrology, soils, vegetation and animals, reduce and limit the amount of chemicals and soil leaving the site, reduce the potable water usage, and to respond to the ecological factors of the project site within the larger watershed.

Required Performance Criteria

Guidelines other than S.2D apply to all projects designated New Buildings and Major Renovations with site work site scope that includes an area of site disturbance that is greater than 3,000 s.f. OR Area of imperviousness (footprint of building plus site impervious area) renovated that is greater than 2,000 s.f..

Guideline S.2D applies for all projects which include renovation or replacement of plumbing fixtures. Major Renovation projects must faucets and showerhead in the renovated area shall be upgraded with low-flow products. Major Renovation projects may otherwise limit performance criteria application to the number of fixtures included in the renovation scope.

  1. Stormwater quantity and watershed connections. Water leaving the project site is subject to the following:
    1. Site water cycle requirements: The project site shall manage stormwater to meet the required percentage of site infiltration, evapotranspiration, and runoff according to its soil types, as evaluated using the Minnesota Impact Design Standard (MIDS) calculator and based on an annual evaluation. Additional requirements for A and B soils located in the uplands and lowlands of the watershed are listed under Part 2 below:
      Hydrological Soil GroupsInfiltration at Least:Evapotranspiration at Least:Onsite Reuse:Runoff Not to Exceed:Total Onsite Managed
      A Soils:
      1.63-0.8 in./hr.      		100%
      		0%0%0%100%
      B Soils:
      0.45-0.3 in./hr.       		50%40%5%5%95%
      C Soils:
      0.2 in./hr.
      		30%55%7%8%92%
      D Soils:
      0.006 in./hr.      		0%60%25%15%85%
      1. Infiltration rates based on onsite testing shall be used, infiltration volume is reported as “Annual Runoff Removed by BMPs” in the MIDS calculator.
      2. Additional infiltration above the percentage required may be used to meet evapotranspiration and onsite reuse requirements.
      3. Additional evapotranspiration may be used to meet onsite reuse requirements.
      4. Infiltration rates and location shall be subject to both water table vulnerability (https://gisdata.mn.gov/dataset/water-aquifer-vulnerability) and ground water contamination susceptibility (https://www.dnr.state.mn.us/whaf/about/scores/geomorphology/g_i_psnsm.html.)
      5. Sites or areas of sites prohibited from infiltration per the NPDES Permit Application Requirements are permitted to satisfy the total onsite managed requirements using other listed means.
      6. Onsite roof-collected rainwater may be used to offset infiltration requirements at a rate of 1 to 1, subject to the guidance below:
        1. Roof-collected rainwater can be employed without treatment when first-flush technology is utilized. Ensure compliance with local plumbing codes.
        2. Roof-collected rainwater shall be prioritized to supplement the site’s water holding requirements and used for one of the onsite designated uses in the following order (some of these may require additional purification). Ensure compliance with local plumbing codes.
          1. For animal habitat per S.1 and S.5: Water should be held in locations to which site animals can have continual water access.
          2. For subsurface irrigation of the site planting.
          3. For evaporative cooling on flat roofs (roof-collected rainwater only, from “blue roofs”).
          4. For cooling towers (roof-collected rainwater only).
          5. For nonpotable water usage (depending on use may be rainwater only).
          6. For toilet flushing (roof-collected rainwater cleaned to a potable standard).
    2. Watershed connections: (Note that if the project is within a watershed district or management organization’s jurisdiction there may be other requirements for the site not listed here).
      1. For projects located in the uplands of the watershed and in Hydrologic Soil Group A: High Infiltration or in Hydrologic Soil Group B: Moderate Infiltration, infiltration of all rainfall events should be planned for a 25-year, 24-hour rain event for project area.
      2. For projects located in the lowlands and Hydrologic Soil Group A: High Infiltration or in Hydrologic Soil Group B: Moderate Infiltration, infiltration of all rainfall events should be planned for a 10-year, 24-hour rain event for project area.
      3. The features of the site’s location in the watershed or lakeshed, and any site-watershed features should be used to inform the design of the site.
    3. Flood prevention: If required by building program to construct within a flood plain, the project shall follow the Federal Emergency Management Agency’s (FEMA) regulatory flood protection elevation requirements. Building in a floodplain is prohibited unless essential to the program of the project.
    4. Runoff rate: The site shall be designed to not exceed the pre-settlement runoff rate for native soil and vegetation conditions, as evaluated by achieving compliant curve numbers (CN) per Natural Resources Conversation Service (NRCS) TR-55 below those of the pre-settlement condition.
  2. Stormwater quality:
    1. Provide treatment systems designed to remove 80% of the post-development Total Suspended Solids (TSS) and 60% of the post-development Total Phosphorus (TP). The design of the retention of TSS and TP shall be accomplished with best management practices and calculated using the MIDS calculator.
    2. The reduction of chlorides shall be accomplished by:
      1. Reducing the area of ongrade impervious surfaces requiring chlorides by 20%.
      2. Reducing the amount of chlorides on the remaining impervious surfaces by employing the Minnesota Pollution Control Agency (MPCA) Winter Maintenance Assessment tool as operational practice.
      3. Developing a chloride management plan for site operations to ensure ongoing chloride-use limits.
      4. Inclusion of planning of alternative measures to de-ice (e.g. utilization of sand, incorporation of snow-melt systems).
  3. No potable water shall be used for irrigation after a 5-year plant establishment period except for periods when actual rainfall for the month is less than 30% of the average rainfall for that month. Collected roof rainwater and graywater may be used for plant irrigation at any time. Turf grass integral to the program of the site, such as athletic fields or school recreational fields are excluded from the calculation for this requirement.
  4. Municipal potable water or harvested groundwater use in building shall be reduced by 50% compared to a baseline established on the 1992 Energy Policy Act requirements and including water-consuming appliances for all uses associated with fixture types referenced by those requirements. The criteria may be met by any combination of the following: selection of low or no-flow fixtures, use of recycled rainwater, or other strategies.
      1. Renovation portions of projects may limit performance criteria application to the number of fixtures included in the renovation scope subject to the following exemption:
        1. Faucets in the renovated area shall be upgraded with low-flow faucet aerators, and showerheads shall be upgraded with low-flow showerheads even if other plumbing fixtures are not upgraded.
      2. Recycled rainwater can also be used to offset the percentage of potable water usage, if allowed in the local jurisdiction.
      3. To verify compliance with this guideline during operation of building, it is necessary to submeter indoor water consumption separately from irrigation.

Recommended Performance Criteria

  1. No potable water shall be used for irrigation after a two-year plant establishment period except for periods when actual monthly rainfall is less than 30% of the average rainfall for that month. Graywater may be used for plant irrigation.
  2. Municipal potable water or harvested groundwater use in building shall be reduced by 70% compared to code (1992 Energy Policy Act requirements) for all uses associated with fixture types referenced by those requirements. The criteria may be met by any combination of the following: selection of low or no-flow fixtures, use of alternatively sourced water, or other strategies. Major Renovation Path projects may limit performance criteria application to the number of fixtures included in the renovation scope.

Employ the Minnesota’s Minimal Impact Design Standard calculator at https://stormwater.pca.state.mn.us/index.php/MIDS_calculator to design the best management practices (BMPs) for the project site to meet the amount of rainwater required to infiltrate project site, amount of rainwater required to evapotranspirate on project site, and amount of rainwater allowed to run off project site.

Storm events are listed under NOAA ATLAS 14: https://www.fws.gov/midwest/planning/MinnesotaWMDs/index.html.

Use the Soil Survey Geographic Data Base (SSURGO), Minnesota at https://gisdata.mn.gov/dataset/geos-ssurgo to determine the hydrological soil group(s) for project site. Employ the MIDS calculator located at https://stormwater.pca.state.mn.us/index.php/MIDS_calculator to design a site that meets the rainwater retention requirements with BMPs.

Water network connections can be determined by using the following resources:

Note: If the project is in a designated area, contact the organization for other specific requirements for the site.

Soil hydrology is determined using the Soil Hydrology of the United States page: http://resources.arcgis.com/en/communities/soils/02ms00000008000000.htm. Determine which of the following drain classes are contained on the site:

  1. Excessively Drained
  2. Somewhat Excessively Drained
  3. Well Drained
  4. Moderately Well Drained
  5. Somewhat Poorly Drained
  6. Poorly Drained
  7. Very Poorly Drained

Based on the drainage designation at ATLAS 14 rainfall estimates (available at https://hdsc.nws.noaa.gov/hdsc/pfds/pfds_map_cont.html).

The site’s flood plain designation should be based on FEMA mapping (listed using FEMA’a National Flood Hazard Layer viewer at http://fema.maps.arcgis.com/home/webmap/viewer.html?webmap=cbe088e7c8704464aa0fc34eb99e7f30), which includes the following designations:

  1. 1% Annual Chance Flood Hazard (under consideration)
  2. Regulatory Floodway
  3. Special Floodway
  4. Area of Undetermined Flood Hazard
  5. 2% Annual Chance Flood Hazard
  6. Future Conditions 1% Annual Chance Flood Hazard
  7. Area with Reduced Risk Due to Levee

If the site is designated as any of the previous categories, contact the county flood plan maps by county at ftp://ftp.dnr.state.mn.us/pub/waters/floodplain/County_data/ to verify FEMA designation. Any sites or portion of sites in designated floodplain areas should not include building construction unless it is essential to the building program. If a building is necessary, it must meet the regulatory flood protection elevation, as listed at http://www.dnr.state.mn.us/waters/watermgmt_section/floodplain/rfpe.html.

Perform soil infiltration test(s) on project site using methods listed in the Minnesota Stormwater Manual, determining soil infiltration rates located at https://stormwater.pca.state.mn.us/index.php?title=Determining_soil_infiltration_rates. Use the infiltration test(s) to compare with the infiltration rates of the hydrological soil group(s) located at https://stormwater.pca.state.mn.us/index.php?title=Design_infiltration_rates. Use the more restrictive infiltration estimate for project site design.

The onsite retention of TSS, phosphorus, and nitrogen can be calculated by applying the selected design strategies via the MIDS calculator and reporting results.

A 20% reduction in the impervious areas that need chlorides may be accomplished through design; the remainder may be removed by the following strategies:[1]

A chloride management plan with the goal of creating a chloride-free site in ten years (https://stormwater.pca.state.mn.us/index.php?title=Chloride_Management_Plan) may include the following:

  1. Use of sand substitution (from first-year occupancy).
  2. Use of alternate salts such as magnesium chloride (after two years of occupancy).
  3. Use of substitute alternatives to reduce chloride, such as beet juice (after four years of occupancy).

The irrigation water use shall be metered and recorded for at least five years after building occupancy or until site planting is fully established. No potable water shall be used for outdoor use such as sidewalks, driveways, or vehicle washings. In addition, no potable water shall be used to irrigate or water after five years of plant establishment except during periods of drought. During periods of drought, potable water irrigation and watering is permitted to ensure plant survival. It is recommended that 90% of plant materials are drought tolerant and that decorative plants only require irrigation for non-severe droughts. Periods of severe drought are defined as months in which monthly rainfall is 70% less than average. Captured rainfall can be used anytime for irrigation and watering of plant materials.

Worksheet S-2 Building Water Calculator should be used to calculate building water use for base and design. This also calculates the base-case condition for Energy Policy Act required flow and flush fixture rates, and provides example fixture performance values for uses associated with those fixtures. Annual water consumption must be submitted to the B3 Guidelines Tracking Tool for a period of ten years after building occupancy through the B3 Benchmarking program.

The proposed graywater treatment system shall meet the environmentally feasible, acceptable soil infiltration condition, and the onsite graywater wetland treatment system or the manufactured graywater treatment system shall be cost effective. The volume of graywater and the required size of the graywater treatment train or manufactured systems shall meet the NSF/ANSI 350 and 350-1, Onsite Water Reuse Treatment Systems standards for the intended final use. If blackwater onsite water treatment is pursued, then a qualified professional should be employed to meet the NSF/ANSI 350 and 350-1, Onsite Water Reuse Treatment Systems standards. Treated blackwater shall not be reused but can be used to supplement a site’s infiltration requirements if the treated blackwater is infiltrated through underground drainage fields.

The watershed on which the project site is located can be found using the website https://app.wikiwatershed.org/ and selecting US Geological Survey (USGS) Subwatershed Unit (HUC-12) for the selected boundary, then selecting the “free draw” area, and then selecting the Continental US Medium Resolution for Delineate Watershed. Under the Layers subheading: For streams, select Continental US Medium Resolution Stream Network; for coverage grid, select Hydrologic Soil Groups from gSSURGO; for boundary, select USGS Subwatershed Unit (HUD-12); for observation, select EPA Permitted Point Sources; for base map, select Terrain. If the project site has soils in Hydrologic Soil Group A: High Infiltration or Hydrologic Soil Group B: Moderate Infiltration, plans should include at least 10% higher infiltration of all rainfall events.

[1] MPCA – Chloride reduction strategies

Predesign:

  • 2A: Submit a map of the watershed with the project site located within the watershed boundaries.

Design:

  • 2A: Submit the requirements for infiltration, evapotranspiration, and runoff derived from MIDS Calculation. Provide the identification of watershed or lakeshed of the project, drainage class(es) of the site, watershed organization jurisdiction, and identified watershed location if Soil Groups A or B is present, including planned rainfall infiltration if site soils include Soil Group A or B and are in the uplands or lowlands of watershed. Note the flood plain designation of the site. Submit completed Excel document demonstrating compliance with infiltration and other on-site managed criteria. Provide additional calculations as necessary to document evapotranspiration contribution to meeting guideline criteria.S.2B: Upload the completed MIDS Calculator demonstrating intended removal systems for required TSS and phosphorus reductions. Also submit map of the watershed with the project site located within the watershed boundaries with slopes (percent of each gradation on site 0%, 1%, 2%, etc.), hydrological classification of the soils by gSSURGO legends (percent of each soil type, A, B, C, etc.). Submit a site plan with identified micro-catchments or buffers, if required per guideline.
  • 2C (and S.2E, if pursuing): Submit base and design case outdoor water consumption, any alternatively sourced outdoor water used, updated completed Outdoor Water Calculator documenting required reduction from base case, and confirmation that drought-tolerant plants have been selected.
  • 2D (and S.2F, if pursuing): Submit base and design case indoor water consumption, any alternatively sourced indoor water used, updated completed Building Water Calculator documenting required reduction from base case, and verification that site contractor understands the requirements and intents of this guideline.

Final Design:

  • 2A: Provide documentation of final project site design demonstrating conformance with the project site requirements concerning infiltration, evapotranspiration, and runoff. List of significant watershed features incorporated into the final project site design, and indication of compliance with additional rainfall infiltration if site soils include Soil Group A or B and are in the uplands or lowlands of watershed.
  • 2B: Upload the completed MIDS Excel document documenting design’s removal systems for required TSS and phosphorus reductions. Provide narrative of chloride reduction methods.
  • 2C (and S.2E if pursuing): Updated base and design case water use. Submit verification that all plant materials are either drought tolerant or can live without potable water after plant establishment period.
  • 2D (and S.2F if pursuing): Submit updated base and design case indoor water consumption, any alternatively sourced indoor water used, and updated completed Building Water Calculator documenting required reduction from base case.

Closeout:

  • 2B: Submit the Watershed Organization Inspection Report on the stormwater system’s installation.
  • 2C: Confirmation that the site contractor and building operator understand the intent of this guideline.
  • 2D (and S.2G if pursuing): Provide updated base and design case indoor water consumption, any alternatively sourced indoor water used, updated completed Building Water Calculator documenting required reduction from base case, and verification that site contractor understands the requirements and intents of this guideline.

Occupancy – Submitted annually for ten years:

  • 2A: As required by the installation manual, document any required inspection and monitoring at prescribed intervals the onsite graywater wetland treatment system or the manufactured graywater treatment system to ensure proper functioning and water quality safety.
  • 2B: Conduct annual inspection of stormwater infrastructure and BMPs to ensure proper functioning. This inspection could be coordinated with the expertise and resources of the local watershed district. Submit bi-year inspection report on BMPs structures. For the first, second, fourth, seventh, and tenth year, submit chloride management plan reports on incremental elimination of chloride loading onsite.
  • 2D: Report on potable or harvested groundwater indoor water consumption.

‘Understanding Site and Water in B3 Version 3.1’ Training Session Video (YouTube)

‘Understanding Site and Water in B3 Version 3.1’ Training Session Slides (PDF)

Additional Resources

Appendix S-2c: Outdoor Water Calculator

Appendix S-2d: Building Water Calculator

Model My Watershed Technical Documentation: https://wikiwatershed.org/documentation/mmw-tech/#layers-viewable-mapped-data.

Description of Gridded Soil Survey Geographic (gSSURGO) Database: https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/survey/geo/?cid=nrcs142p2_053628.

Soil Hydrology of the United States: http://resources.arcgis.com/en/communities/soils/02ms00000008000000.htm.

Web Soil Survey (WSS): https://websoilsurvey.nrcs.usda.gov/app/.

Minnesota Soil Survey Status by County: https://stormwater.pca.state.mn.us/index.php?title=File:Minnesota_soil_survey_status.png.

Natural Vegetation of Minnesota at the Time of the Public Land Survey 1847–1907:

http://files.dnr.state.mn.us/eco/mcbs/natural_vegetation_of_mn.pdf OR

http://www.mngeo.state.mn.us/chouse/land_use_historic.html OR

https://gisdata.mn.gov/dataset/biota-marschner-presettle-veg

Marschner Maps: http://discussions.mnhs.org/collections/wp-content/uploads/2008/09/092_marschner.jpg.

Digital Soil Mapping in Minnesota: http://www.mngeo.state.mn.us/chouse/soil.html.

Soil Survey Geographic Database (SSURGO), Minnesota: https://gisdata.mn.gov/dataset/geos-ssurgo.

Soils and Landscapes of Minnesota by James Anderson, Jay Bell, Terry Cooper, and Dave Grigal: https://extension.umn.edu/soil-management-and-health/soil-orders-and-suborders-minnesota.

Average Annual Precipitation in Minnesota Cities: https://www.usclimatedata.com/climate/minnesota/united-states/3193.

Minnesota’s Minimal Impact Design Standard Overview: https://stormwater.pca.state.mn.us/index.php/Overview_of_Minimal_Impact_Design_Standards_(MIDS).

Minnesota’s Minimal Impact Design Standard Calculator: https://stormwater.pca.state.mn.us/index.php/MIDS_calculator.

Minnesota Stormwater Manual Design infiltration Rates: https://stormwater.pca.state.mn.us/index.php?title=Design_infiltration_rates.

Smart Salting Training Website: https://www.pca.state.mn.us/water/training.

Chloride Management Plan: https://stormwater.pca.state.mn.us/index.php?title=Chloride_Management_Plan.

Road Salt & Water Quality Website: http://www.pca.state.mn.us/programs/roadsalt.html.

Winter Parking Lot and Sidewalk Maintenance: https://www.pca.state.mn.us/sites/default/files/p-tr1-10.pdf.

Winter Maintenance Assessment Tool (WMAt): https://stormwater.pca.state.mn.us/index.php/Winter_Maintenance_Assessment_tool_(WMAt)

Winter Parking Lot and Sidewalk Maintenance Factsheet: https://stormwater.pca.state.mn.us/index.php?title=Winter_Parking_Lot_and_Sidewalk_Maintenance_Factsheet.

The Real Cost of Salt Use for the Winter: https://www.pca.state.mn.us/sites/default/files/wq-iw11-06bb.pdf.

Smart Salting Certified Contractors: https://www.pca.state.mn.us/sites/default/files/p-tr1-01.xlsx.

MPCA Smart Salting Level 1 Certification: Buildings and Sidewalks https://www.pca.state.mn.us/water/salt-application-training.

MPCA Smart Salting Level 2 Certification: Road Maintenance Organizations https://www.pca.state.mn.us/water/salt-application-training.

Snow Removal: Do It Better, Cheaper, and Pollution-Free: https://www.pca.state.mn.us/news-and-stories/snow-removal-do-it-better-cheaper-and-pollution-free

Improved Winter Maintenance: Good Choices for Clean Water Mississippi Watershed Management Organization: https://www.youtube.com/watch?v=qc8Y-_Nmfmo.

Drought Tolerate Plants: https://stormwater.pca.state.mn.us/index.php?title=Minnesota_plant_lists.

Minnesota Native Plant Encyclopedia: https://www.dnr.state.mn.us/rys/pg/encyclopedia.html.

Living Landscape in Minnesota: https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_022410.pdf.

Rainwater Harvesting: https://rainwaterharvesting.tamu.edu/rainwater-basics/.

How to Use Native Plants for Landscaping and Restoration in Minnesota:

Home Is Where the Habitat Is: https://www.dnr.state.mn.us/mcvmagazine/issues/2015/mar-apr/gardening-with-native-plants.html.

MN DNR Native Plant Suppliers and Landscapers Listing: https://www.dnr.state.mn.us/gardens/nativeplants/suppliers.html.

DNR Restore Your Shore Program: https://www.dnr.state.mn.us/gardens/nativeplants/suppliers.html.

MN DNR Invasive Species Listings: https://www.dnr.state.mn.us/invasives/index.html.

MN DNR Prescribed Fire Information: https://www.dnr.state.mn.us/firewise/prescribed.html.

MNTaxa Vascular Plants of Minnesota: https://www.dnr.state.mn.us/eco/mcbs/plant_lists.html.

DNR Information on Transplanting Lady’s-Slipper Orchids: http://files.dnr.state.mn.us/assistance/backyard/gardens/native_plant/orchidtransplanting.pdf.

Minnesota Board of Water and Soil Resources, Native Vegetation/Seed Mixes: http://www.bwsr.state.mn.us/native_vegetation/index.html.

University of Minnesota Extension – Native Plants for Sustainable Landscapes.

Minnesota’s Pollinators: https://www.dnr.state.mn.us/pollinators/index.html.

References for Plant Identification and Minnesota Ecology: http://files.dnr.state.mn.us/eco/nhnrp/annotated_bibliography.pdf.

Library of Rainwater Collection System Designs: http://www.rainharvest.com/library-of-rainwater-collection-system-designs.asp.

Design Criteria for Stormwater and Rainwater Harvest and Use/Reuse in Minnesota: https://stormwater.pca.state.mn.us/index.php?title=Design_criteria_for_stormwater_and_rainwater_harvest_and_use/reuse.

National Stormwater Calculator: https://www.epa.gov/water-research/national-stormwater-calculator.

Sample Specification for a Rainwater Catchment System: http://www.harvesth2o.com/adobe_files/ARCSA_Rainwater%20Code.pdf.

The Texas Manual on Rainwater Harvesting 2005: http://www.harvesth2o.com/adobe_files/ARCSA_Rainwater%20Code.pdf.

EPA Graywater Treatment Using Constructed Wetlands: https://cfpub.epa.gov/si/si_public_record_Report.cfm?dirEntryId=246852.

Constructed Wetlands for the Treatment of Grey Water in Campus Premises: https://link.springer.com/content/pdf/10.1007%2F978-3-319-11961-8_25.pdf.

NSF/ANSI 350 and 350-1, Onsite Water Reuse Treatment Systems: http://www.nsf.org/services/by-industry/water-wastewater/onsite-wastewater/onsite-reuse-water-treatment-systems.

Small-Scale Constructed Wetlands for Graywater and Total Domestic Wastewater Treatment: https://www.sswm.info/sites/default/files/reference_attachments/WAFLER%202008%20Small%20scale%20Constructed%20Wetlands.pdf.

Graywater Works: www.grayworks.com.

Englehardt, James D., Wu, Tinnting, and Tchobanoglus, George. 2013. “Urban Net-Zero Water Treatment and Mineralization: Experiments, Design.” Water Research, 47. https://www.ncbi.nlm.nih.gov/pubmed/23770482.

Guo, Tianjiao and Englehardt, James D. 2015. “Principles for Scaling of Distributed Direct Potable Water Reuse Systems: A Modeling Study.” Water Research, 75. https://www.ncbi.nlm.nih.gov/pubmed/25768987 Or file:///C:/Users/stron081/AppData/Local/Packages/Microsoft.MicrosoftEdge_8wekyb3d8bbwe/TempState/Downloads/Urban_NetZero_water_treatment_mineralization.pdf

Steiner, Lynn. Landscaping with Native Plants of Minnesota. Voyageur Press, 2011: https://www.amazon.com/Landscaping-Native-Plants-Minnesota-2nd/dp/0760341184.

Wester, Julia, Timpano, Kiara R., Cek, Demet, Lieberman, Debra, Fieldstone, Shaina C., and Broad, Kenneth. 2015.“Psychological and Social Factors Associated with Wastewater Reuse Emotional Discomfort.” Journal of Environmental Psychology, 42. https://pdfs.semanticscholar.org/3b84/1faeb402047056d71694c22032f9f1a0b9aa.pdf.

Glossary

Graywater Treatment:

Treatment of graywater must employ a preferred natural reed bed/wetland treatment and infiltration system or a reed bed/wetland treatment and recapture system for all onsite use where there is site space available, or, for tight urban spaces, treatment of graywater can employ an onsite manufactured treatment system for infiltration.

Environmentally Feasible:

If sufficient infiltration is feasible on the site (not an MPCA contaminated soils site), the treatment wetland is part of the required area for the animal and vegetative habitat and an asset to the design of the site.

Acceptable Soil Infiltration Conditions:

Natural or engineered soil must be able to treat and infiltrate or treat graywater onsite at the required rate during winter conditions.

Cost Effective:

Applies to situation in which the treatment of graywater per gallon is less expensive on a total cost basis (initial cost, operating cost over 20 years based on a discounted cash flow) than a potable water option.

Wetland Type Descriptors:[1]

  • Precipitation-Dominated Wetlands
    • Bogs: Bogs obtain water primarily from precipitation and are characterized by sphagnum mosses dominating the floor of the bog and creating waterlogged, acidic conditions with low nutrient levels (USEPA 2010). Bogs prevent downstream flooding by absorbing precipitation. Because of the acidic, waterlogged conditions and low nutrient levels, only species that are specifically adapted to such conditions are able to live in bogs, resulting in many unique plant and animal species (USEPA 2010).
    • Pocosins: Pocosins are shrub- and tree-dominated landscapes with little standing water located at a slightly higher elevation than the surrounding landscape. Precipitation is the main water source, and although there is little standing water, the soil is saturated much of the year, resulting in waterlogged, nutrient-poor, and acidic soils. Fires typically occur in pocosins every ten to 30 years during the spring or summer dry periods, and pocosins play a key role in maintaining a diverse tree and shrub population (USEPA 2010).
    • Vernal Pools, Playas, Prairie Potholes, Wet Meadows, and Wet Prairies: Because of many similarities, these wetland types are sometimes categorized as marshes; however, unlike marshes, they receive water predominately from precipitation. Because these wetlands are isolated from surface waters, they do not typically discharge to surface waters, but many recharge groundwater (North Carolina State University [NCSU] Water Quality Group n.d.).
  • Surface Water-Dominated Wetlands:
    • Marshes: Marshes are generally defined as wetlands frequently or continually inundated by water. All types of marshes receive most of their water from surface water; some are also fed by groundwater. Their vegetation is characterized by emergent soft-stemmed plants adapted to saturated soil conditions. Marshes are home to an abundance of plant and animal life due to high nutrient levels and neutral pH (USEPA 2010). They play an important role in recharging groundwater supplies, moderating stream flow, and settling pollutants to improve water quality (NCSU Water Quality Group n.d.).
    • Riparian Forested Wetlands: These wetlands receive water from rivers, streams, and lakes and are located across the United States. Standing water is present in the winter and spring, with little to no standing water during the summer and fall (NCSU Water Quality Group n.d.). Riparian forested wetlands act as a sink for pollutants from nonpoint sources (USEPA 2010). They also receive alluvial soil from floods, and as a result, they are very productive and are important ecologically as they serve as habitat for plant and animal species (NCSU Water Quality Group n.d.).
    • Fens: Fens are very similar to bogs, the main distinction being that fens receive water from groundwater (NCSU Water Quality Group n.d.). Fens are peat-forming wetlands; they have less acidic soil conditions and higher nutrient levels than bogs. Fens are located in northern regions characterized by low temperatures and short growing seasons (USEPA 2010). They can contribute to downstream waters and stabilize water tables by recharging groundwater at local aquifers (NCSU Water Quality Group n.d.).

[1] EPA Region 5 Wetlands Supplement: Incorporating Wetlands into Watershed Planning, March 2012.