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In addition to water quality concerns, improperly managed snow can lead to water quantity issues, such as flooding and erosion. | In addition to water quality concerns, improperly managed snow can lead to water quantity issues, such as flooding and erosion. | ||
+ | |||
+ | ===Regulatory implications=== | ||
+ | There are no specific regulatory requirements regarding snow storage in NPDES stormwater permits. Proper snow storage may facilitate meeting NPDES requirements. For example, snow storage may result in pollutant load reductions to impaired waters having approved <span title="The amount of a pollutant from both point and nonpoint sources that a waterbody can receive and still meet water quality standards"> [https://stormwater.pca.state.mn.us/index.php?title=Total_Maximum_Daily_Loads_(TMDLs) '''total maximum daily loads''']</span>. | ||
+ | |||
+ | The next section provides a discussion of potential restrictions for snow storage. | ||
===Siting recommendations=== | ===Siting recommendations=== | ||
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</div> | </div> | ||
+ | '''Considerations''' | ||
*Identify <span title="A stream, river, lake, ocean, or other surface or groundwaters into which treated or untreated wastewater is discharged"> '''receiving waters'''</span> and assess the risk to them. Although identifying the contribution of <span title="Baseflow (also called drought flow, groundwater recession flow, low flow, low-water flow, low-water discharge and sustained or fair-weather runoff) is the portion of streamflow delayed shallow subsurface flow".> '''baseflow'''</span> to receiving waters can be challenging, it is important if meltwater will infiltrate and recharge groundwater. Potential receiving waters include the following. | *Identify <span title="A stream, river, lake, ocean, or other surface or groundwaters into which treated or untreated wastewater is discharged"> '''receiving waters'''</span> and assess the risk to them. Although identifying the contribution of <span title="Baseflow (also called drought flow, groundwater recession flow, low flow, low-water flow, low-water discharge and sustained or fair-weather runoff) is the portion of streamflow delayed shallow subsurface flow".> '''baseflow'''</span> to receiving waters can be challenging, it is important if meltwater will infiltrate and recharge groundwater. Potential receiving waters include the following. | ||
**Streams and rivers with a significant baseflow component | **Streams and rivers with a significant baseflow component | ||
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**Lakes and wetlands with limited baseflow | **Lakes and wetlands with limited baseflow | ||
**Groundwater | **Groundwater | ||
+ | **[https://stormwater.pca.state.mn.us/index.php?title=Special_Waters_and_Impaired_Waters Special waters] - identify receiving waters with temperature-sensitive species (e.g. trout) | ||
+ | **[https://stormwater.pca.state.mn.us/index.php?title=Special_Waters_and_Impaired_Waters Impaired waters] - identify impaired waters and the pollutant(s) of impairment | ||
*Consult with your local community or municipality for technical guidelines on snow site management and operations. | *Consult with your local community or municipality for technical guidelines on snow site management and operations. | ||
*Estimate how much snow disposal capacity is needed for the season so that an adequate number of disposal sites can be selected and prepared. Plan on snow storage capacity equal to 20-30 percent of the snow volume from the source area. | *Estimate how much snow disposal capacity is needed for the season so that an adequate number of disposal sites can be selected and prepared. Plan on snow storage capacity equal to 20-30 percent of the snow volume from the source area. | ||
*Determine potential pollutants of concern from the snow source areas. The following table provides general guidance for identifying pollutants associated with specific land uses, but be aware that local conditions affect the presence or absence of potential pollutants of concern. In particular, be aware of [https://stormwater.pca.state.mn.us/index.php?title=Potential_stormwater_hotspots potential stormwater pollutant hotspots]. | *Determine potential pollutants of concern from the snow source areas. The following table provides general guidance for identifying pollutants associated with specific land uses, but be aware that local conditions affect the presence or absence of potential pollutants of concern. In particular, be aware of [https://stormwater.pca.state.mn.us/index.php?title=Potential_stormwater_hotspots potential stormwater pollutant hotspots]. | ||
*Considering potential pollutants of concern, when practicable, designate snow storage areas in locations that enable runoff to be directed to stormwater BMPs for treatment prior to discharge to a receiving water, including groundwater. For inforation on potential pollutants of concern for surface water or groundwater, [https://stormwater.pca.state.mn.us/index.php?title=Surface_water_and_groundwater_quality_impacts_from_stormwater_infiltration see this link]. | *Considering potential pollutants of concern, when practicable, designate snow storage areas in locations that enable runoff to be directed to stormwater BMPs for treatment prior to discharge to a receiving water, including groundwater. For inforation on potential pollutants of concern for surface water or groundwater, [https://stormwater.pca.state.mn.us/index.php?title=Surface_water_and_groundwater_quality_impacts_from_stormwater_infiltration see this link]. | ||
+ | *In addition to water quality and quantity considerations, evaluate other factors such as increased cost of transporting snow, increased carbon emissions associated with transport, aesthetics, and public acceptance. | ||
{| class="wikitable" | {| class="wikitable" | ||
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− | + | '''Restrictions''': Snow storage should be avoided in the following areas. Note that storage may be prohibited in some of these situations. | |
− | + | *In a receiving water (e.g. lake, river, wetland) | |
− | + | *Within a floodplain | |
− | + | *Within 100 feet of active karst or areas where fractured bedrock is within 50 feet of the land surface | |
− | + | *Within setback distances from receiving waters | |
− | + | *On permeable soils (<span title="A soil classification system (Natural Resource Conservation System) based on runoff potential. Groups include A soils (coarse textured with very low runoff potential), B soils (medium coarse textured with low runoff potential), C soils (fine to moderate textured with moderate runoff potential), and D soils (fine textured with high runoff potential)."> '''[https://stormwater.pca.state.mn.us/index.php?title=Design_infiltration_rates hydrologic soil group]'''</span> A) where infiltration is not recommended or is prohibited under the Minnesota Construction Stormwater General Permit | |
− | + | *In sanitary landfills, quarries, and gravel pits unless the site does not pose a high risk to groundwater and can meet the criteria for a good location | |
− | + | *In sections of parks or playgrounds that will be used for direct contact recreation after the snow season | |
− | * | + | *In locations that result in blockage of drainage ditches or other stormwater conveyance |
− | *Prioritize potential sites based on the following selection criteria. | + | *Avoid snow storage when discharges may affect a [https://stormwater.pca.state.mn.us/index.php?title=Special_Waters_and_Impaired_Waters special or impaired water]. Examples include meltwater in close proximity to trout waters or having elevated concentrations of a pollutant causing a surface water impairment. |
− | + | ||
− | + | '''Preferred conditions''': Prioritize potential sites based on the following selection criteria. | |
− | + | *Upland sites are preferred | |
− | + | *Slopes should be less than 6 percent, with slopes less than 2 percent preferred | |
+ | *Site that can be used indefinitely are preferred, particularly if the site can be engineered to minimize environmental impacts | ||
+ | *Preference is for storage on permeable material that meets typical stormwater design standards found in the Minnesota Stormwater Manual (e.g. 3 feet separation to seasonal high water table) | ||
+ | *Generally, snow should be stored in areas where meltwater discharges to low or less vulnerable receiving waters. For example, meltwater that discharges directly to large order rivers (e.g. Mississippi River) or large lakes (e.g. Lake Superior) is favorable unless there are specific concerns with the discharge. | ||
===Site recommendations=== | ===Site recommendations=== | ||
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*Assess and if necessary, rehabilitate the infiltration capacity of the storage area and confirm conveyance facilities are functional. | *Assess and if necessary, rehabilitate the infiltration capacity of the storage area and confirm conveyance facilities are functional. | ||
*Monitor the quality of snowmelt | *Monitor the quality of snowmelt | ||
+ | *Snow melting is generally discouraged, particularly if done in close proximity to receiving waters | ||
+ | |||
+ | ==Recommendations for on-site storage of snow== | ||
+ | [[File:Snow plowed and piled in parking lot.jpg|thumb|300px|alt=Photo showing Snow plowed and piled in parking lot|<font size=3>Snow plowed and piled in parking lot. Consideration should be given in locating these "snow dumps", since they will contribute a significant amount of stormwater runoff.]]</font size> | ||
+ | |||
+ | [[File:Plowed snow off parking lot to grass area.jpg|thumb|300px|alt=Photo showing Plowed snow off parking lot to grass area|<font size=3>Photo showing plowed snow off parking lot to grass area]]</font size> | ||
+ | |||
+ | On-site storage of snow is typically associated with parking areas. Snow is pushed from impervious surfaces to one or more locations adjacent to or in the parking area. | ||
− | ===References for snow disposal and storage | + | The same basic principles of snow storage discussed above apply to on-site storage. This includes [https://stormwater.pca.state.mn.us/index.php?title=Guidance_and_recommendations_for_storing_transported_snow_and_for_on-site_snow_storage#Siting_recommendations siting recommendations], [https://stormwater.pca.state.mn.us/index.php?title=Guidance_and_recommendations_for_storing_transported_snow_and_for_on-site_snow_storage#Site_recommendations site recommendations], and [https://stormwater.pca.state.mn.us/index.php?title=Guidance_and_recommendations_for_storing_transported_snow_and_for_on-site_snow_storage#Inspection_and_maintenance inspection and maintenance]. |
+ | |||
+ | There are a number of additional considerations specific to on-site storage, as discussed below. | ||
+ | *Locate snow piles down-slope from pollutant sources, such as salt and sand storage areas, to prevent snow melt from flowing through salt or sand storage areas | ||
+ | *Store snow on permeable surfaces to the extent possible | ||
+ | *Minimize drainage onto the parking area by correctly siting the snow storage pile(s) with respect to slope, drainage pathway, and by placing drains in close proximity and directly down-gradient of snow storage areas | ||
+ | *Ensure snowmelt does not drain to sidewalks and adjacent streets | ||
+ | *If feasible, drain snowmelt to stormwater BMPs. Tree trenches and other underground practices are most suitable. | ||
+ | *Minimize erosion by incorporating appropriate [https://stormwater.pca.state.mn.us/index.php?title=Erosion_prevention_practices erosion prevention] and [https://stormwater.pca.state.mn.us/index.php?title=Sediment_control_practices sediment control] practices | ||
+ | *Mark the edges of the area to be plowed and of the snow storage area. This reduces the risk of damage from plowing and storage. | ||
+ | *Consider landscaping the area, following the tips [https://stormwater.pca.state.mn.us/index.php?title=Guidance_and_recommendations_for_storing_transported_snow_and_for_on-site_snow_storage#Landscaping_for_snow_storage_areas in this section] | ||
+ | *Ensure snow plow equipment can easily access the area to be plowed and the snow storage area | ||
+ | *Clear snow as soon as possible while it’s still easy to move | ||
+ | |||
+ | ==Landscaping for snow storage areas== | ||
+ | Certain landscape design features may be incorporated into snow storage areas to make them more aesthetically pleasing or to provide other functions. Examples include the following. | ||
+ | *Incorporate plants into the site design | ||
+ | **Choose plants that are salt-tolerant | ||
+ | **Coniferous vegetation is preferred to provide year-round aesthetic value | ||
+ | **Trees and shrubs are preferred | ||
+ | Keep pervious snow storage areas mulched to enhance infiltration and minimize compaction | ||
+ | *Locate snow piles in areas that can be easily maintained and cleaned following snowmelt | ||
+ | *Ensure that landscaped areas on the location are adequately protected from snow piles, equipment, and negative impacts associated with melting. | ||
+ | |||
+ | ==References for snow disposal and storage== | ||
*Alaska Department of Environmental Conservation, Division of Water. [https://dec.alaska.gov/water/wastewater/stormwater/snow-disposal/snow-disposal-guidance/ Snow Disposal Site Selection Guidance] | *Alaska Department of Environmental Conservation, Division of Water. [https://dec.alaska.gov/water/wastewater/stormwater/snow-disposal/snow-disposal-guidance/ Snow Disposal Site Selection Guidance] | ||
*Carlson, Robert F., David L. Barns, Nathanael Vaughan, Anna Forsstrom. 2003. [http://www.dot.state.ak.us/stwddes/research/assets/pdf/fhwa_ak_rd_03_04.pdf Synthesis of Best Management Practices for Snow Storage Areas]. University of Alaska, Fairbanks. Department of Civil and Environmental Engineering. Alaska Department of Transportation and Public Facilities Research & Technology Transfer. FHWA-AK-RD-03-04. September. | *Carlson, Robert F., David L. Barns, Nathanael Vaughan, Anna Forsstrom. 2003. [http://www.dot.state.ak.us/stwddes/research/assets/pdf/fhwa_ak_rd_03_04.pdf Synthesis of Best Management Practices for Snow Storage Areas]. University of Alaska, Fairbanks. Department of Civil and Environmental Engineering. Alaska Department of Transportation and Public Facilities Research & Technology Transfer. FHWA-AK-RD-03-04. September. | ||
*Johannessen, M., and A. Henriksen. 1978. ''Chemistry of snow meltwater: Changes in concentration during melting''. Water Resources Research. 14:4:615-619. https://doi.org/10.1029/WR014i004p00615 | *Johannessen, M., and A. Henriksen. 1978. ''Chemistry of snow meltwater: Changes in concentration during melting''. Water Resources Research. 14:4:615-619. https://doi.org/10.1029/WR014i004p00615 | ||
− | *Lake Tahoe Stormwater Management Program. 2014. [https://tahoebmp.org/ | + | *Keep it Clean Partnership. [https://www.keepitcleanpartnership.org/wp-content/uploads/2021/12/Salt-Sand-and-Deicer-Storage-and-Snow-Disposal-BMP.pdf Stormwater Best Management Practices Salt, Sand and Deicer Storage & Snow Disposal] |
+ | *Lake Tahoe Stormwater Management Program. 2014. [https://tahoebmp.org/Documents/BMPHandbook/Chapter%204/4.2/c_SnwStrg.pdf Snow Storage]. Chapter 4-2c. | ||
+ | *Love Your Landscape.org. [https://www.loveyourlandscape.org/expert-advice/landscaping-essentials/seasonal-guide-to-lawn-and-landscape-care/safe-snow-removal-protect-your-landscape-protect-yourself/ SAFE SNOW REMOVAL: PROTECT YOUR LANDSCAPE AND YOURSELF]. Accessed February 9, 2022. | ||
*Massachusetts Department of Environmental Protection Bureau of Water Resources. 2020. [https://www.mass.gov/doc/2020-snow-disposal-policy-and-guidance/download Snow Disposal Guidance]. | *Massachusetts Department of Environmental Protection Bureau of Water Resources. 2020. [https://www.mass.gov/doc/2020-snow-disposal-policy-and-guidance/download Snow Disposal Guidance]. | ||
*Municipality of Anchorage. 2017. [http://anchoragestormwater.com/ Management and Design Criteria Manual]. Volume 1, Chapter 8. | *Municipality of Anchorage. 2017. [http://anchoragestormwater.com/ Management and Design Criteria Manual]. Volume 1, Chapter 8. | ||
− | |||
*Reinosdotter, K. 2007. [https://www.diva-portal.org/smash/get/diva2:998901/FULLTEXT01.pdf Sustainable Snow Handling]. Doctoral Thesis. Luleå University of Technology. | *Reinosdotter, K. 2007. [https://www.diva-portal.org/smash/get/diva2:998901/FULLTEXT01.pdf Sustainable Snow Handling]. Doctoral Thesis. Luleå University of Technology. | ||
*Urban Drainage and Flood Control District. 2010. [https://mhfd.org/wp-content/uploads/2019/12/S-10-Snow-and-Ice-Management.pdf Snow and Ice Management]. Urban Storm Drainage Criteria Manual Volume 3. | *Urban Drainage and Flood Control District. 2010. [https://mhfd.org/wp-content/uploads/2019/12/S-10-Snow-and-Ice-Management.pdf Snow and Ice Management]. Urban Storm Drainage Criteria Manual Volume 3. | ||
*Wheaton, S.R. and W.J. Rice, 2003. [http://anchoragestormwater.com/Documents/siting_design_ops_snowdisp_sites.pdf Siting, design and operational controls for snow disposal sites]. In Proceedings - Urban Drainage and Highway Runoff in Cold Climate, March 25-27, 2003, Riksgränsen, Sweden, pp.85-95. | *Wheaton, S.R. and W.J. Rice, 2003. [http://anchoragestormwater.com/Documents/siting_design_ops_snowdisp_sites.pdf Siting, design and operational controls for snow disposal sites]. In Proceedings - Urban Drainage and Highway Runoff in Cold Climate, March 25-27, 2003, Riksgränsen, Sweden, pp.85-95. | ||
+ | |||
+ | [[Category:Level 2 - Management/Winter management]] |
This page provides recommendations for managing and storing snow. It includes information for snow collected from impervious surfaces and transported to a storage location as well as information on storing snow on-site. The recommendations focus on protection of surface waters (lakes, rivers, wetlands), except where otherwise noted.
NOTE: This page only provides a general overview of snowmelt dynamics, instead focusing on snow storage. Numerous references are included throughout this page and the reader is referred to those for more detailed information. This manual also has a page on Cold climate impact on runoff management which provides a comprehensive discussion of cold climate considerations for managing urban stormwater and stormwater practices, including information on snowmelt runoff and snow management.
Snow packs experience multiple freeze-thaw cycles through the winter and early spring. This results in partial melting and channelized flow of meltwater in the snowpack. Soluble pollutants are preferentially transported with this meltwater and accumulate near the base of the snowpack, while particulates are filtered during these partial melts. This accounts for the high release of soluble pollutants in the early phases of the melt.
Oberts (2010) described a three stage melt process in urban areas.
Characteristics of snowmelt
Link to this table
Early | Middle | Late | X |
---|---|---|---|
Character | |||
High soluble content | Remaining solubles, beginning of fine- to medium-solids | High solids content | |
Low runoff volume, early infiltration | Large runoff volume | Large runoff volume (especially if rain-on-snow occurs), saturated soils | |
Initiated by chemical addition and/or solar radiation | Largely driven by solar radiation, aided by salt | Solar driven |
The quality of runoff from melted snow is affected by the dynamics of snowmelt. The following information was extracted from the literature.
Water quality of snowmelt differs from non-winter runoff.
Recommended references
This section provides guidance and recommendations for managing snow from impervious surfaces that is transported (trucked) to a snow storage area, where the snow is stockpiled and allowed to melt. The guidance includes information on identifying appropriate snow storage areas, storing snow in those areas, and operations and maintenance of snow storage areas.
Snow may be removed from an impervious surface for several reasons, including but not limited to the following.
Snow removed from an impervious surfaces contains a variety of pollutants, including sediment, coarse organic material, nutrients, chloride, metals, and hydrocarbons. Melted snow may create an oxygen demand and have other impacts on water quality, such elevated or reduced pH. These pollutants can impact receiving waters.
The previous discussion on dynamics and water quality impacts of snowmelt are applicable to meltwater from a snow storage area. The table below provides a general summary of pollutants associated with different source areas for the snow.
In addition to water quality concerns, improperly managed snow can lead to water quantity issues, such as flooding and erosion.
There are no specific regulatory requirements regarding snow storage in NPDES stormwater permits. Proper snow storage may facilitate meeting NPDES requirements. For example, snow storage may result in pollutant load reductions to impaired waters having approved total maximum daily loads.
The next section provides a discussion of potential restrictions for snow storage.
For more information, see [1], [2], [3], [4], [5], [6], [7]. |
Considerations
Pollutants of concern for different land uses | |||||||
Land use | Sediment | Phosphorus | Nitrogen | Metals | Organics | Chloride | BOD |
---|---|---|---|---|---|---|---|
Residential | X | X | X | ||||
Commercial | X | X | X | ||||
Industrial | X | X | X | X | |||
Transportation | X | X | X | X | |||
Park | X | X | X | ||||
Parking lot | X | X |
Restrictions: Snow storage should be avoided in the following areas. Note that storage may be prohibited in some of these situations.
Preferred conditions: Prioritize potential sites based on the following selection criteria.
On-site storage of snow is typically associated with parking areas. Snow is pushed from impervious surfaces to one or more locations adjacent to or in the parking area.
The same basic principles of snow storage discussed above apply to on-site storage. This includes siting recommendations, site recommendations, and inspection and maintenance.
There are a number of additional considerations specific to on-site storage, as discussed below.
Certain landscape design features may be incorporated into snow storage areas to make them more aesthetically pleasing or to provide other functions. Examples include the following.
Keep pervious snow storage areas mulched to enhance infiltration and minimize compaction
This page was last edited on 2 February 2023, at 14:39.