Zoning to Enhance Maryland’s Green Infrastructure

North County Preservation—Executive Summary of Secondary Research and GIS Based Assessment

August 29, 2007

 

In anticipation of the Comprehensive Zoning Map Process (CZMP), the North County Preservation is issuing reports summarizing research about the environmental and quality of life issues which zoning decisions impact.  These reports, in conjunction with North County Preservation’s CZMP Geographic Information System (GIS), will help Baltimore County residents assess proposed zoning changes in terms of their environmental and quality of life impacts.  This report concerns the Maryland Green Infrastructure, as identified by Maryland’s Department of Natural Resources (DNR).

 

CZMP AND GREEN INFRASTRUCTURE IN BALTIMORE COUNTY

EXECUTIVE SUMMARY

 

When an ecosystem’s functions break down (such as cleansing water and filtering air), it is both costly and difficult to repair, often taking a toll on the health of plant, animal, and human populations.  The Maryland Department of Natural Resources (DNR) developed the Green Infrastructure Assessment to identify ecologically important lands and provide decision support for Maryland's land conservation programs.  The database also identifies Green Infrastructure Gaps of developed, mined, or cleared lands within the green network.  It is critical that policy makers take steps to bridge these gaps and protect and further enhance the Green Infrastructure and its benefits to the environment and our quality of life.

 

The Maryland Board of Public Works (consisting of the Governor, Treasurer, and Comptroller) recently adopted enhancement of Green Infrastructure as a major criterion for the State’s purchase of lands with property transfer tax monies.  This action confirms the importance of assessing the impact on Green Infrastructure of each rezoning request submitted during Baltimore County’s upcoming Comprehensive Zoning Map Process (CZMP).

  

GREEN INFRASTRUCTURE – WHAT IS IT?

 

Green Infrastructure includes corridors of forests, wetlands, and other natural lands that provide the bulk of the State’s ecological support system.  In northern Baltimore County, the Green Infrastructure is significant in its importance and extent, benefiting the Gunpowder River, Prettyboy Watershed, and Loch Raven Watershed.  Maps show that approximately 25% of the County is identified as Green Infrastructure (GI), and much of the rest of northern Baltimore County abuts the GI.  Even more striking on the maps are the Green Infrastructure Gaps along streams that, if reforested, would benefit wildlife, improve water quality, and provide stream stabilization.   

 

A recent study conducted by the Conservation Fund suggests that a healthy watershed should have forests over more than 40% of the area and impervious surfaces over less than 10%.  Impervious surfaces, such as roadways and sidewalks, have a negative impact by reducing natural uptake and filtering systems, and contributing to soil erosion and pollutant runoff into streams.

 

Over the years, road construction and residential and commercial development have reduced the Green Infrastructure, thereby diminishing the many important benefits it provides to area residents and the overall ecosystem.  The loss of forested areas has contributed to more severe drought conditions, soil erosion, storm water runoff, and air pollutants. 

 

This is because the Green Infrastructure provides natural filtration that enhances water and air quality.  Also, the ecosystem’s functions conserve soils, regulate climate, and provide vital habitat to wildlife, including sensitive species in and around forested areas. The environmental benefits provided by the Green Infrastructure (air and water purification, temperature moderation) affect the greater region as well, especially by protecting the quality of water in the Gunpowder River, which provides drinking water to the Baltimore Metropolitan area.  The Green Infrastructure also is an effective means for preserving the State’s biodiversity and natural resources, including Forested Interior Dwelling Species of animals, plants and insects that require forest habitat for optimal survival and reproduction.

 

THE RELEVANCE OF GREEN INFRASTRUCTURE TO CZMP ZONING DECISIONS

 

Baltimore County’s Comprehensive Zoning Map Process (CZMP), which reoccurs every four years, is underway.  Decisions will be made in the upcoming months regarding the zoning and land use of every property within Baltimore County.  It is imperative that planners, the County Council, and the County Executive make zoning decisions that protect and enhance the Green Infrastructure and protect our natural resources. 

 

North County Preservation (NCP), Inc., a coalition of community associations in northern Baltimore County, urges the protection of the Green Infrastructure.  To help citizens and County planners identify properties worthy of preservation from development, NCP developed a Geographic Information System (GIS).  This database has layers of information about every County property, which are used for mapping and analysis.  One of the GIS’s most important layers is the DNR’s Maryland Green Infrastructure and Gaps in Baltimore County.  For information, you may check out NCP’s website at www.northcountypreservation.org or contact NCP’s President Irving Spitzberg at ijs@northcountypreservation.org.  See the attached research and maps.  For more information about Baltimore County’s Green Infrastructure, contact Renae Olver at rolver1@hotmail.com or Jeff Gernand at jgernand3@yahoo.com

 

CZMP ACTION TO PROTECT AND ENHANCE GREEN INFRASTRUCTURE

 

Baltimore County decision-makers should assess all rezoning decisions during the CZMP based on potential impact to the Green Infrastructure.  Development should not be allowed on properties in or adjacent to Green Infrastructure corridors, or properties with the same attributes but which have not yet been cataloged and mapped.  To assist with decision-making, the County should update its maps of Green Infrastructure Corridors and its Green Infrastructure Database.
 

CZMP AND GREEN INFRASTRUCTURE IN BALTIMORE COUNTY

 

Background:  Maryland continues to face rapid urbanization, resulting in the consumption of an excessive amount of land, fragmentation of the landscape, displacement of native species, and disruption of ecosystem functions.1-3   Clean air, clean water, soil conservation, and climate regulation are all vital to the overall health of people, wildlife, native plants, and other organisms.  Maryland’s undeveloped areas such as forests, wetlands and other natural lands provide the bulk of the ecological support systems, particularly critical in watershed environments.1-3

 

This research summary includes the results of a collaborative project of the Maryland Department of Natural Resources (DNR) and The Conservation Fund to develop a systematic approach for identifying land conservation and restoration priorities in Maryland. 1   This project created a geographical information database.  Its purpose is to target areas that serve the ecosystem and enhance water and air quality through natural filtration processes, and also conserve soils, regulate climate, and provide vital habitat to wildlife including sensitive species in and around forested areas.  These natural processes are very important since they contribute to the quality of life for North County residents.  The database also includes a component for identify gaps of developed, mined, or cleared lands within the green network.  The objective is to bridge these areas and further protect and enhance the infrastructure and its overall benefit to our natural environment.

 

Action:  North County Preservation strongly urges Baltimore County to protect the Green Infrastructure as identified by the DNR.  Baltimore County decision-makers should assess all rezoning decisions during the CZMP based on the potential impact to the Green Infrastructure.  Development should not be allowed on properties in or adjacent to Green Infrastructure corridors, or properties with the same attributes but which have not yet been cataloged and mapped.  To assist with decision-making, the County should update its maps of Green Infrastructure Corridors and its Green Infrastructure Database.

 

Technical Basis:  Land development in Baltimore County must restrict development in the Green Infrastructure in order to limit deforestation, flooding, desertification, and reduction of habitat to wildlife and plants (including sensitive species native to the area).  Roadways and commercial or residential development within these corridors would result in the loss of land that is considered critical to the natural environment and the ecosystem’s support.  These corridors provide natural systems that reduce air and water pollution. Further negative impact on northern Baltimore County’s Green Infrastructure would reduce the health and quality of life of area residents.

 

Maryland has lost more than half of both its forested areas and wetlands since colonization.  According to the Maryland Green Infrastructure Analysis, as of 2001 slightly less than half (48%) of Baltimore County’s Green Infrastructure is considered protected land.  Hence, 46,613 out of 83,144 acres (52%) still remain unprotected and at risk for potential development.  In Maryland, the Green Infrastructure accounts for about 33% of all land, and 39% if gaps are included (areas that are similar and connect existing GI land).  The Green Infrastructure also includes 63% of Maryland’s interior forests, 89% of streams with brook trout, 89% of Maryland’s steep slopes, 88% of threatened or endangered species, and 91% of Maryland’s streams with interior forests. 1-3

 

Forests help clean the air by removing large amounts of CO2.  In Maryland, it has been estimated that vegetation absorbs 55 million metric tones of CO2 annually (Strebel, 2002).  Additionally, forests help absorb sulfur dioxide and release oxygen.  However, the Maryland Department of Planning estimates that the tree canopy in the Chesapeake Bay Watershed declined from 55% to 38%, from 1997 to 2002.  According to a study by American Forests (1999), trees lost in the Baltimore-Washington corridor between 1973 and 1997 could have removed 9.3 million pounds of air pollutants annually, a function valued at $24 million a year.1-3

 

The same tree loss is estimated to have increased storm water runoff by 19%, costing roughly $1 billion.  This is because Green Infrastructure absorbs storm water and recycles it through the hydrologic system, which may reduce pollution and control runoff and flooding.  American Forests estimated that retaining forests helps protect against erosion and the resulting stream sedimentation.  However, the development of road networks can result in alteration of drainage and catastrophic erosion.  The natural hydrologic cycle contrasts with what happens when impervious, developed areas prevent water infiltration.  In fact, the U.S. Department of Agriculture, Natural Resources Conservation Service (NRCS) estimated that water runoff develops ten times faster on developed land as compared to unaltered landscape (Moore, 2002).

 

Rainwater that falls on developed land is not recycled.  By slowing surface runoff and providing opportunities for settling and infiltration, forests help remove nutrients, sediments, and other pollutants.  Infiltration rates in forests of the Green Infrastructure are commonly 10-15 times higher than for grass turf and 40 times higher than for a plowed field (Chesapeake Bay Program, 2000).  Tree roots remove nutrients from settled runoff and ground water, and store them in leaves and wood. Through the process of denitrification, bacteria in the forest floor convert harmful nitrate to nitrogen gas, which is released into the air (Chesapeake Bay Program, 2000). In stream and river floodplains, vegetation traps and removes water-borne particulates during storms. Riparian forest buffers have proven to be effective at reducing nutrient loads in areas that have largely been deforested. Studies have demonstrated reductions of 30 to 98 percent for nitrogen, phosphorus, sediments, pesticides, and other pollutants in surface and ground water after passing through a riparian forest (Chesapeake Bay Program, 2000).1-3

 

The Green Infrastructure also benefits the stream networks and reservoirs through ground water recharge and other natural processes.  Plants trap some of the rainfall, and some percolates down to aquifers.  Water stored on the surface or below ground provides drinking water for humans and wildlife, keeps plants alive, and assists in stream base flow in dry periods.  According to the Maryland Department of the Environment (MDE), about half of all stream flow originates as ground water (Moore, 2002).  

 

The increase in drought conditions of recent years has been suspected as a direct effect of tree losses over the last two centuries (Olson, L, date unknown).  Eighteen of Maryland's counties were on drought watch in the fall of 2001, making it the third driest autumn since 1871 (US Water News, 2002).  In January 2002, Baltimore’s reservoirs were at the lowest point on record, and Baltimore City had to start pumping 50 million gallons of water a day from the Susquehanna River (US Water News, 2002). The Susquehanna itself was running at only 36% of its normal flow (US Water News, 2002). Additionally, low flows put the Monocacy River off-limits, drastically reducing the available water supply for the City of Frederick, one of the fastest growing cities in Maryland (US Water News, 2002) .3

 

Gaps or areas that connect Green Infrastructure corridors should also be protected from development. As forests become isolated or separated due to roads or commercial or residential development, wildlife habitat and migration levels are lost, and the environment’s ability to absorb nutrients, recharge water supplies, replenish soils is diminished.  Maryland's diversity and vitality depend on the composition of its landscape: its geology, climate, water, soils, flora, and fauna. They serve as vital habitat for resident and migratory species, maintain a vast genetic library, provide scenery, and contribute in many ways to the health and quality of life for Maryland residents.  Habitat loss and fragmentation can have a detrimental impact on plants and animals, often leading to low diversity in the ecosystem and less efficiency in supporting populations (Odum, 1983).  Patches of fragmented land may result in ecological traps with insufficient resources for certain concentrations of birds or other animals (Heske, 1999).1-3

 

References:

1.         Quoted excerpts taken from 2006 Maryland Department of Natural Resources website page “Maryland’s Green Infrastructure.”  http://dnr.maryland.gov/greenways/gi/gi.html.

2.         Conservation Fund, The. 2000. Welcome to the Green Infrastructure. Net Website:  Providing a Strategic Framework for Smart Conservation. [Online] Available at:  http://greeninfrastructure.net/

3.         Maryland’s Green Infrastructure Assessment.  A Comprehensive Strategy for Land Conservation and Restoration. [Online]  Available at:  http://dnrweb.dnr.state.md.us/download/bays/gia_doc.pdf/

  

NOTE:  MAPS OF THE GREEN INFRASTRUCTURE ARE AVAILABLE FROM NORTH COUNTY PRESERVATION’S CZMP GIS.  ATTACHED PLEASE FIND THE NCP CZMP GIS BITMAP FILE SHOWING THE EXTENSIVE GREEN INFRASTRUCTURE NETWORK WITHIN BALTIMORE COUNTY.