Description: Green Infrastructure Network MappingNatural areas and gaps between, within, and adjacent to them have been mapped into a Countywide green infrastructure network. Natural Areas include streams, forests, wetlands, and non-forest habitat within the mapped network. These areas form the existing green infrastructure network elements that have the potential to be further connected, enhanced, conserved, restored, and protected.The map uses four general network categories: “Regulated” Areas Other Protected Lands Evaluation Areas Network Gaps Based on whether the land cover within “Regulated Areas and Other Protected Lands is natural areas, or gaps within, between, or adjacent to natural areas, the network is classified into a total of six mapping categories:Natural Areas in “Regulated” AreasNetwork Gaps in “Regulated” AreasNatural Areas in Other Protected LandsNetwork Gaps in Other Protected LandsEvaluation AreasOther Network GapsThe four general green infrastructure network categories and the six mapping categories are described below. “Regulated” Areas“Regulated”Areas include environmentally sensitive features and their buffers such as streams, wetlands (where mapped in GIS), and 100-year floodplains, that are protected during the land development process by laws, guidelines, or regulations, and meet minimum criteria for inclusion in the network. “Regulated”Areas are the areas along stream corridors (based on GIS data) that have a minimum width of existing forest, non-forest habitat managed by the Department of Parks, or unmanaged non-forest habitat discernable on aerial photographs, on bothsides of the stream. “Regulated”Areas also include stream segments that do not meet the minimum natural area buffer coverage criteria, but provide potential linkages between stream segments that do meet the minimum criteria, or between other significant natural resources. In “Regulated”Areas, preservation is the main focus and development is not generally permitted except for necessary construction of road crossings and installation of public utilities. Quotation marks in the “Regulated”Area category designation are used to indicate that these areas are only rough approximations of the areas that are regulated in the development review process. One reason for this is that the network map was based on County-scale GIS data, which are less accurate than site-specific data. Another reason is that other natural features that are used in determining regulated areas, such as steep slopes or erodible soils, need to be determined using field-verified data, and are not factored into the Countywide map. In addition, because “Regulated”Areas incorporate only those areas that meet the minimum criteria for inclusion within the green infrastructure network, the network map includes most, but not all, of the natural areas in the County that may be regulated. As a result, the Green Infrastructure Network Map is not a substitute for site-specific evaluations of natural resources,including those required for development review, but should always be used together with field-verified data. “Regulated” Areas are mapped using two sub-categories:Natural Areas in “Regulated”Areas- Streams, forests, wetlands, and non-forest habitats within “Regulated”AreasNetwork Gaps in “Regulated”Areas(Described below under Network Gaps)- Discontinuities between Natural Areas in “Regulated”Areas"Regulated” Area Mapping CriteriaGreen Infrastructure Network Analysis AreasIn setting the mapping criteria for “Regulated” Areas within the network the County was divided into three Green Infrastructure Mapping Analysis Areas based on comparative density of development: The Urban Ring (as defined in the General Plan), The Primary Funding Area (PFA) outside of the Urban Ring, and Outside of the PFA. Development density generally increases (and the mapping criteria for “Regulated” Area more inclusive) as one moves from the area outside of the PFA, to the PFA outside of the Urban Ring, to the Urban Ring. Mapping criteria are more inclusive with increasing density because of the significant loss of stream corridors over time in urban areas, and the heightened importance of those that remain in these areas. “Regulated” Area stream corridors in the network were mapped at 200 feet, 250 feet, or 300 feet in width depending on the State Water Use Class, per the County’s current Environmental Guidelines for Development (Maryland-National Capital Park and Planning Commission, 1997). As described above, the “Regulated” Area corridor widths were also expanded to include the 100-year floodplain, and GIS-mapped wetlands and ponds and their buffers that are within, or contiguous with, the “Regulated” Area corridors. Until a revised version of the Environmental Guidelines for Development is promulgated, the approximate buffers for streams within the Ten Mile Creek watershed will be shown per the current Environmental Guidelines. Criteria for Corridor Inclusion in the NetworkOutside of the Primary Funding Area:Minimum 200-foot wide stream corridors that are covered by forest, non-forest habitat buffer managed by the Parks Department, or unmanaged non-forest habitat discernable by aerial photographsStream segments that do not meet the minimum criteria for natural area buffer coverage, but provide potential linkages between stream segments that do meet the minimum criteria, or other significant natural resources Priority Funding Areas outside of the Urban Ring:Minimum 100-foot wide stream corridors that are covered by forest, non-forest habitat buffer managed by the Parks Department, or unmanaged non-forest habitat discernable by aerial photographsStream segments that do not meet the minimum criteria for natural area buffer coverage, but provide potential linkages between stream segments that do meet the minimum criteria, or other significant natural resourcesUrban Ring:No minimum width criterion for stream corridor existing habitat buffer coverage Other Protected LandsOther Protected Lands includes existing lands that are protected primarily for their natural value by Local, State, and Federal government. These areas include:Existing M-NCPPC Parkland of the following types:Best Natural Areas,Biodiversity Areas,Stream Valley Parks,Conservation Parks,Neighborhood Conservation Parks, and Managed Open Natural Areas within these Parks, such as meadowsAll of the above parklands were included in the network except for several Neighborhood Conservation Parks that are very small and located more than 600 feet* from the network. Existing Federal and State ParksAlthough some of the parks listed above have some non-natural areas within them such as agricultural land and park facilities, they are mostly natural lands. These areas will continue to be maintained and managed, by the respective government landowners as parklands that are recognized for the importance of the values and functions of their natural areas.Category 1 Forest Conservation Easements including:Category 1Offsite (Category 1)Bank (Category 1)Category 1 Forest Conservation Easements 5 acres and greater in size1and within 600 feet2of the network were included in the network by linking them with a network gap area. Some easements smaller than 5 acres, however, when located closer to the network, were also included in the network.Washington Suburban Sanitary Commission (WSSC) Lands (source water protection)These are lands owned and managed by WSSC as natural areas (predominantly forested) that provide protection for drinking source waters.1The 5-acre criterion is based on guidance from the Audubon Society regarding minimum habitat area needed to support key migratory bird species (Audubon New York).2The 600-foot distance criterion is based on published data and is the distance beyond which forest birds typically tend not to fly across gaps between forested areas (St. Clair, Belisle, Desrochers and Hannon, 1998; Harris and Reed, 2002).Other Protected Lands are mapped using two sub-categories:Natural Areas in Other Protected LandsStreams, forests, wetlands, and non-forest habitats within Other Protected LandsNetwork Gaps in Other Protected Lands(Described below under Network Gaps)Discontinuities between Natural Areas in Other Protected Lands“Regulated” Areas within Other Protected Lands are mapped as “Regulated” Areas.Evaluation AreasEvaluation Areas are natural areas adjacent to or near “Regulated”Areas or Other Protected Lands, that have the potential to form larger protected natural corridors through preservation, and through connection with existing corridors if currently separated by gaps. Evaluation Areas should be examined during the development review, park planning, and other master planning processes. This will help determine which non-regulated natural resources, if protected, would best serve to enhance the network, or to identify areas where restoration or mitigation could better serve to expand or connect adjacent resources. Evaluation Areas may contain environmentally sensitive features such as forest or special habitats, and they should be given high priority on such issues as onsite forest and habitat conservation during the development review and master planning processes. Development review, park plans, and other master plans in these areas should consider protection of natural resources, or non-forest tree canopy creation, in places that optimize network connectivity. Network GapsNetwork Gaps are natural area discontinuities within the green infrastructure network that may provide opportunities to revegetate and enhance connectivity within and between “Regulated” Areas, Other Protected Lands, and Evaluation Areas. Potential connections in upland areas across watershed divides were also identified and mapped. When restored or enhanced, Network Gaps can increase connectivity within the network, and increase the acreage of forest, non-forest habitat such as meadows, and non-forest tree canopy. During the development review, park planning, and other master planning processes, Network Gaps should be evaluated to determine the potential to improve green infrastructure connectivity. Discontinuities between natural areas that met the green infrastructure mapping criteria were mapped as gaps regardless of the underlying land use or cover. As a result, it should be noted that not all of the land within Network Gaps will be suitable or practicable for habitat or tree canopy enhancements. Many gaps in the network will remain gaps because of the existing land use and cover, or plans for future development. Again, site-specific data are necessary in evaluating mapped gaps for potential network enhancements. In other cases, site-specific evaluations may show a mapped gap to be a non-forested natural area, and therefore not a gap. Network Gaps, therefore, provide a general guide, which, when augmented by more detailed site-scale study, can aid in identifying potential sites for habitat enhancement, or other green area enhancements short of habitat creation, that can still provide increased green connectivity values. For example, Network Gaps in developed areas that are not suitable for establishing additional woodlands may provide opportunities to enhance green connectivity by increasing non-forest tree canopy, such as street trees. In any case, the conceptual network map can provide information regarding potential opportunities for enhancing local and Countywide natural area connectivity that might not otherwise be recognized and considered.Network Gaps are mapped using three sub-categories:Network Gaps in “Regulated” Areas (Mentioned above under “Regulated”Areas)Discontinuities within forest and managed non-forest managed habitats within “Regulated” Areas are mapped as Network Gaps in “Regulated Areas. These gaps, however, may include non-forest habitats that are not managed by the Parks Department or mapped in GIS, which should be identified and evaluated during site-specific investigations to determine whether it would be preferable to reforest them or leave them as non-forest successional habitat. Network Gaps in “Regulated” Areas will generally have a higher priority for restoration or protection because of their proximity to aquatic features such as streams and wetlands.Network Gaps in Other Protected Lands (Mentioned above under Other Protected Lands)Network Gaps on Other Protected Lands are discontinuities within forest and non-forest managed habitats that occur on lands that are already protected primarily for the forest and non-forest natural values of the land. Some of the parklands in the Other Protected Lands category may have some non-natural areas within them such as farmland and park facilities. As with Network Gaps in “Regulated” Areas, these gaps may include unmanaged or unmapped non-forest habitats. In such cases, site-specific evaluations will help to determine whether it would be preferable to reforest these areas or leave them as non-forest successional habitat. In any case, Other Protected Lands will continue to be maintained and managed by the respective government landowners under their current policies, plans, and programs. In the course of implementing park plans, such as the County’s PROS Plan and specific park or natural resource management plans, some of the gaps on these lands may be reforested or revegetated over time. As with Network Gaps, Network Gaps on Other Protected Lands that are not suitable for reforestation due to existing land use and cover, or planned park development, may still provide opportunities to enhance green area connectivity by increasing non-forest tree canopy.Gaps on Other Protected Lands mapped within Category 1 Conservation Easements may be indicative of tree stands that have died, tree plantings that have not yet occurred or failed in part or in whole, potential violations of the easements, or easements that predate the Forest Conservation Law. Other Network GapsOther forest and non-forest managed habitat discontinuities are mapped as Other Network Gaps. These are typically within Evaluation Areas or between Evaluation Areas and “Regulated” Areas or Other Protected Lands. Due to the lower detail of map data available on a Countywide scale, Other Network Gaps may include unmapped non-forest habitats, which should be evaluated during site-specific evaluations to determine whether it would be preferable to reforest them or leave them as non-forest successional habitat. Open areas on golf course lands are included as Other Network Gaps because they are relatively large open spaces, and network connections and ecological functions could potentially be strengthened if they are proposed for redevelopment in the future. Future Updates of the Green Infrastructure Network Map and Tracking Increases in Natural Area Coverage and ConnectivityUpdates to the green infrastructure network map will be made from time to time, when needed to reflect accumulated changes on the ground. The use of two basic land cover types, Natural Areas and Network Gaps, will facilitate future map revisions and tracking increases in natural area coverage and connectivity. The Commission’s land cover data is regularly updated, which supports identifying changes in land cover compared with earlier data. Likewise, additions and changes to the park system and Category 1 forest conservation easements are also included in regular GIS layer updates, allowing for future revisions to the Other Protected Lands category. Priority Considerations for Habitat Mitigation, Restoration, Enhancement, Protection, Conservation, and Acquisition within the Green Infrastructure NetworkThe Green Infrastructure Network Map provides information on potential locations for enhancing natural area and tree canopy health and connectivity that can be used in existing planning, regulatory, and programmatic processes related to natural area mitigation, restoration, enhancement, protection, conservation, or acquisition. Depending on which of these are the goals, enhancement or protection of certain areas within the green infrastructure network can often provide higher potential environmental benefits than other areas, and opportunities for network enhancement can be ranked accordingly in terms of relative priority. It should be noted that the following prioritization factors are only a general guide. A thorough analysis of regional and local conditions, resources, and opportunities available for specific enhancement and protection projects may reveal factors that result in different priorities. For example, in urban areas with limited opportunities for natural area creation, the enhancement of urban tree canopy may be a higher priority. Likewise, proximity to identified high quality, priority, or exemplary habitats and biological communities such as Best Natural Areas and Biodiversity Areas, will be important information in setting green infrastructure network protection, restoration, and enhancement priorities and recommendations.Basic factors that should be considered in prioritizing network enhancement opportunities include maximizing the: Location within the Network Headwater areas generally have higher priority than downstream areas. Priority also generally increases with increasing proximity to streams, wetlands, and other water features.Area of natural land that can be connected Length of green corridors that can be createdThe number of currently separated natural lands and corridors that can be connected. In some cases, potential project sites may be given a higher priority because they would significantly facilitate additional future efforts to connect large or important areas. Proximity to identified high quality, priority, or exemplary habitats and biological communities such as Best Natural Areas and Biodiversity Areas, may increase the priority of a potential project within the green infrastructure network. In urban areas where the focus is on tree canopy, the highest priority should be on street trees and other tree canopy that maximizes greenway connections between urban parks and other urban green spaces, and natural areas within or adjacent to the area under consideration.The following lists provide generalized priorities that should be considered in conjunction with the basic factors listed above, and local goals, needs, and opportunities, in decisions regarding natural resource mitigation, restoration, enhancement, protection, conservation, and acquisition within the Green Infrastructure Network. The highest priority should generally be given to areas where green area enhancements would provide the greatest benefits for local and Countywide ecological connectivity and ecological function.Generalized Priorities for Natural Resource Mitigation, Restoration and Enhancement within the Green Infrastructure NetworkNetwork Gaps in “Regulated”Areas within Other Protected Lands Network Gaps in “Regulated”Areas between Other Protected LandsRemaining Network Gaps in “Regulated”Areas Other Network Gaps between Other Protected LandsOther Network Gaps between “Regulated”AreasOther Network Gaps that would increase the area of interior forestOther Network Gaps between Other Protected Lands and Evaluation AreasOther Network Gaps between “Regulated”Areas and Evaluation AreasOther Network Gaps within and between Evaluation Areas Areas within all Network Gaps that are not suitable for habitat restoration but suitable for other environmental enhancements such as urban tree canopy and street treesMaster plans, zoning, and field-verified data will be essential in setting final priorities or sub-priorities for a given area or site.Natural resource mitigation, restoration, and enhancement on Other Protected Lands will continue to be identified and prioritized under the policies, plans, and programs of the respective agency landowners. Generalized Priorities for Natural Resource Protection, Conservation, and Acquisition within the Green Infrastructure NetworkLands containing significant forest or other natural area coverage that are designated as future conservation parkland or identified for natural resource values through the Legacy Open Space Functional Master Plan implementation processNatural Areas in “Regulated”Areas that are not within Other Protected LandsEvaluation Areas contiguous with Natural Areas in “Regulated”AreasEvaluation Areas contiguous with Other Protected LandsNetwork Gaps in “Regulated”Areas between Other Protected LandsNetwork Gaps in “Regulated” Areas that separate significant natural areas in “Regulated”Areas outside of Other Protected LandsEvaluation Areas closest to Other Protected Lands and associated Other Network Gaps Evaluation Areas closest to Natural Areas in “Regulated”Areas and associated Other Network Gaps Remaining Evaluation Areas and associated Other Network Gaps Other Network Gaps across watershed dividesMaster plans, zoning, and field-verified data will be essential in setting final priorities or sub-priorities for a given area or site. Natural resource protection, conservation, and acquisition on Other Protected Lands will continue to be identified and prioritized under the policies, plans, and programs of the respective agency landowners. Green Infrastructure Network Map Applications in Existing Planning, Regulatory, and Programmatic Processes to Enhance Natural Area Health and Connectivity In addition to Montgomery County agencies, many other entities, including local jurisdictions, municipalities, adjoining counties, regional authorities, State and Federal agencies, and non-governmental organizations will be able to use the network map to enhance their efforts to increase, preserve, protect, conserve, restore, enhance, and connect their natural resources. The existing public and private planning, review, and programmatic processes that can potentially use the green infrastructure map as a source of additional information to support environmental decision making are listed below. Maryland-National Capital Park and Planning CommissionPlanning DepartmentDevelopment Review ProcessNatural Resource Identification Natural Resource ProtectionForest Retention and MitigationConservation EasementsPark DedicationMaster Plan Update Analyses and RecommendationsStream BuffersNatural Area Enhancement,Connectivity, andProtectionTree CanopyPark Dedication RecommendationsUpland and Riparian Reforestation Planting ProjectsForest Conservation Banks ProgramUrban Tree Canopy and Street Tree Enhancement ProjectsWater Resources Functional Master Plan ImplementationPatuxent River Watershed Functional Master Plan ImplementationEnvironmental Setting Analyses in Historic Preservation CasesPublic Outreach Tree Planting ProgramsDepartment of ParksPark System Planning, Acquisition, Development, and Management PROS PlanLegacy Open Space Functional Master PlanNatural Resources Management ProgramNatural Resources Management PlanThe Natural Resource Vegetation Management PlanThe Non-Native and Invasive Plant Management PlanPlanting Requirements for Land Disturbing Activities and Related Mitigation on ParklandPark Reforestation ProgramThe Comprehensive Management Plan for White-tailed DeerMeadow Management GuidelinesTree Planting and Invasive Plant Removal Public Outreach ProgramsPark Management PlansNatural Area Identification,Protection,Conservation,Enhancement,Restoration, andManagementPark Development Review ProcessNatural Resource Identification Natural Resource ProtectionForest Retention and MitigationConservation EasementsCountywide Parks Trails PlanWater Quality Permit (TMDL) Planning and ImplementationWashington Suburban Sanitary Commission (WSSC)Source Water Protection Plans and ProgramsReservoir Watershed Management PlansForest Management PlansWater Quality Permit (TMDL) Planning and ImplementationCounty AgenciesDepartment of Environmental Protection (DEP)1. Montgomery County Municipal Separate Storm Sewer System (MS4) Permit Programa. Coordinated Implementation Strategyi. Watershed Restoration Studies Planning and ImplementationStream and Riparian Restoration ProjectsUpland and Riparian Reforestation Projects2. Regional Watershed Feasibility Studies with the US Corps of Engineers to assess potential and locations for water quality improvement practices 3. Tree Montgomery Projects4. DEP’s Watershed Restoration and Outreach Grant Applications5. County Climate Protection Plan Implementation and other Sustainability Efforts6. Forest Preservation Strategy7. Tree Planting Public Outreach ProgramDepartment of Transportation (DOT)Street Tree Planting ProjectsPotential Conversion of Undeveloped Road Rights-of-Way to ParklandMunicipalities, Nearby Counties, Regional Planning Authorities, State Agencies, and Federal AgenciesPark System PlanningPark Management PlansWatershed Protection PlansWater Quality Protection ProgramsAir Quality ProgramsDrinking Source Water Protection PlanningWater Quality Permit ImplementationForest, Wetland, and Tree Canopy ProgramsDevelopment ReviewCoordination with the Montgomery County for Natural Area and Trail ConnectivityPrivate Organizations and Other State ProgramsPrivate Citizen and Other Non-Government Organizations (NGOs)Reforestation ProjectsTree Planting and Canopy Enhancement ProjectsHabitat Enhancement and Maintenance ActivitiesGreen Stormwater Management ProjectsRegional Green Infrastructure InitiativesOther State Land Conservation ProgramsProgram Open SpaceRural Legacy ProgramGreenPrint ProgramMaryland Environmental Trust (MET)The Conservation Reserve Enhancement Program (CREP)The Maryland Agricultural Land Preservation Foundation (MALPF)References CitedAudubon New York: Working Lands—Managing Habitat for shrubland and young forest birdsHarris, R.J. and Reed, J.M., 2002: Behavioral barriers to non-migratory movements of birds. Ann. Zool. Fennici 39: 275-290.Maryland-National Capital Park and Planning Commission, 1997: Guidelines for Environmental Management of Development in Montgomery County.St. Clair, C.C., Belisle, M., Desrochers, A. and Hannon, S.J., 1998: Winter responses of forest birds to habitat corridors and gaps. Conservation Ecology 2(2):13.
Service Item Id: a16e0e8de29e44acbbeb8f2881355285
Copyright Text: Mark Symborski, Eliud De Jesus, Jay Mukherjee