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<br />high water flows, earthquake data, groundwa.
<br />ter, and much else. The Nature Conservancy
<br />(www.nature.org)hasdevelopedeco-regional
<br />plansror many regions of the United States.
<br />Also helpful to planners are the state biodi-
<br />versity plans from Florida, Maryland,and New
<br />Jersey that map important conservation areas.
<br />
<br />ZONING APPLIED
<br />Afterplanners have identified critical and sensi-
<br />tive habitats and species, they shol.lld begin
<br />drafting the zoning regulations. Because of the
<br />diverse needs of species and habitats,prescrip'
<br />tions for a I.lniversalsCllution are impossible.
<br />Still,commonlyuseazoningtoolstocarryo'ut
<br />'protection goalswil\ have some benefit almost
<br />anywhere. Such tools include sensitive areas
<br />districts, overlay zones, critical area designa.
<br />tions, and design review reql.lirements. Other
<br />zoning methods are tailored to the needs of
<br />specific habitats and species, including fencing
<br />controls, river corridor protection regulations,
<br />buffer zones, and tree protection ordinances.
<br />The following section digests most major zoning
<br />
<br />~;;. ~ ~;~~C<, _ !,i~." .~" '. :'~:
<br />
<br />BiodiVl'lSity:Theva~etyoflife and itsproresses,
<br />wlli~b Tn~ludes the variety ofliving organisms,
<br />thege!leti~dTtferencesamongthem, al'ldthe
<br />communities and eeosystems in which they
<br />omrr(pASReportS21/S:;!i).
<br />CritkatArea: InclUdes the following areas and
<br />e~osystems:(1)wetlands;(:2)areaswithacriti-
<br />cal recharging effetl on aqlIifers used for potable
<br />water; (lJ fish and wildlife habftatconservation
<br />areas; (!j)frequentlyfioodedareas;.!s)geologi-
<br />caUyhazardousareas;(6)pondsandlakes;and
<br />(]) streams, creelts,and rivers (Sknmonjo
<br />Counly,Washinglon).
<br />Ecosystern:Theinteratlingsystemofbio\ogical
<br />community and its non-living environmental SW".
<br />mundings (PAS RepoI1S21/~iJ.
<br />EndangeredSpedes:Anyspedeswhichisin
<br />danger of extinction throughout all or a signlfi-
<br />cant portion of its rarrge othertb<ln a spe~ies of
<br />the Class insecta determined by the Secrdary to
<br />constftuteapestwhoseprotectionunderthe
<br />provislonsofthisAdwouldpresentanover-
<br />whelmlngand overriding risk to man {U.S.
<br />FederolE/ldongeredSpedesActl.
<br />Habitat:The physical lot:ation or type of environ-
<br />ment In which an organlsm or biological popula-
<br />tion lives orocc:urs (PAS Repor152l/s22).
<br />ThreatenedSp~des:Anyspecieswhichis likely
<br />to become an endangered spedes within the
<br />foreseeablefuturethroughout all ora significant
<br />portion of its range {US. FedefolEndongered
<br />speciesActl.
<br />
<br />
<br />tools used today by planners with examples
<br />from cities and counties around the country.
<br />Zoning districts. Zoning districts can pro-
<br />tectspeciesthroughuse,density,perform-
<br />ance, and design. For some habItats and
<br />species, prohibiting certain use types-for
<br />example, industry-maybe all that is needed
<br />for protection. Other habitats and species will
<br />undoubtedlyreql.lire a more severe limitation
<br />onthe number and intensity of uses.
<br />Shasta County,Califomia, has a well-
<br />regarded zoning district approach to habitat
<br />protection.Thecounty'shabitatprotectiondis-
<br />tnct protects lands that have significant wildlife
<br />value. Site development standards indudeJlexi-
<br />ble densities, which are determined after the
<br />pro:.::imityofthe proposed developmenttothe
<br />sensitive area is known. Except in the mostsen-
<br />sitive habitat areas, residential densities are
<br />one unit per acre. Densities may be increased if
<br />thedevelopmentisdusteredorifthedeveloper
<br />indudesotherhabitatprotectionmeasures.The
<br />clustered lots must be sited to reduce the
<br />impacts of the development on critical wildlife
<br />habitat components, such as watering sites or
<br />thermal areas.
<br />The maximum reSidential density is five
<br />units per acre inthe most sensitive habitat
<br />areas. Residential clustenng and other habitat
<br />proter.:tion measures are required for all devel-
<br />opmentstothe degree necessary to mitigate
<br />the impacts to the sensitive area.
<br />Overlay districts. Overlay districts are
<br />more common than habitat zoning districts
<br />because of the relative convenience of apply-
<br />inganadditionalsetofissue-specificregula-
<br />tionstoanexistingarea(district(s)).Tucson's
<br />environmental resource zone (ERZ) protects
<br />criticat and sensitive wildlife habitat in east-
<br />em Pima County near Tucson's publlclands
<br />(Saguaro National Park,Coronado National
<br />
<br />Forest,3!ldTuc:;on Mountain Park). The city
<br />began the planning process by mapping criti.
<br />calwildlife, sensitive areas, riparian areas,
<br />and resource corridors. All new development
<br />proposals and subdivisions in those areas
<br />must undergo planning and zoning review for
<br />compliancewiththeoverlayzoningdesigna-
<br />tion.Applicants have two options for develop-
<br />mentunderthe ERZ overlay zoning regula-
<br />tions:Theycan choose notto build in the
<br />loa-year f1oodplain-a sizable area in arid
<br />Arizona-orthl?ycancompleteastudyofthe
<br />corridorthatincludesanenvironmental
<br />resource report and a mitigation plan. Aside
<br />from those two choices, preservation of all of
<br />the critical riparian habitat areas within the
<br />resource corridors is required.
<br />The overlay district aiso Includes require-
<br />mentsforrCiads, bike paths, and sidewalks in
<br />critical riparian habitat areas. Roadways and
<br />paths are normally prohibited in critical areas,
<br />but when essential they have to crossthehabi-
<br />tatarea-theycannotrunparalleltoit~tomini-
<br />mize damage. Theil are also permitted only at
<br />the narrowest points. Utiiities must be placed
<br />underground.Damagetovegetationfromdeve\.
<br />opment in the critical area should be restored
<br />with plant material salvaged from the site.Tne
<br />ordinance also includes standards fur lighting,
<br />fencing, and variances.
<br />The Tucson ordinance is a good example
<br />ofhowcitiescanusedataandnaturalre-
<br />sources maps to draft a poiicy that targets
<br />specific critical habitats and species. Plan.
<br />ners in Tucson found that the critical and sen.
<br />sitive areas were not isolated to a few sites
<br />but were linked to corridors that serve as
<br />important migratory routes and help preserve
<br />gene pool interactionS.
<br />MarinCounty,California'soverlaydls,
<br />trlct for habitat and species protection-the
<br />
<br />ZONING PRACTiCE 1.07
<br />1..ME.RICllNPlANNINGA.SSOCIATIONIP,'9
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