Restoration
Goal 1: Restore the
natural hydrological functioning of the watershed
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1.1
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Restore
Arroyo Seco stream and tributaries through widening and
lengthening of streams.
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1.1.1
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Remove the concrete lined channel,
and replace it with a naturally functioning stream where possible:
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Create meanders and braiding in stream
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Restore floodplains
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1.1.2
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Restore creek tributaries:
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Enhance drainage swales
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Daylight creek tributaries
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1.1.3
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Conduct a
detailed hydraulic analysis of the modified channel and
floodplain.
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1.1.4
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Conduct
a detailed geomorphic analysis to determine an appropriate
combination of channel sinuosity and channel geometry.
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1.1.5
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Formulate program for
multi-objective operation and maintenance of restored system that
is adaptable by all management agencies.
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1.2
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Create floodplain system
allowing for periodic channel overflows while maintaining existing
level of public safety.
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1.2.1
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Mitigate existing flood hazard
conditions.
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1.2.2
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Utilize existing open spaces along
Arroyo Seco and tributaries for floodplain restoration.
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1.3
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Reduce volume and velocity of storm
water runoff.
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1.3.1
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Utilize multiple-purpose BMPs and
management practices such as reforestation, bioengineering, and/or
other non-structural approaches for flood management.
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1.3.2
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Implement flood attenuation measures
in subwatersheds through increased groundwater percolation and
slowing of surface runoff.
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1.3.3
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Utilize non-structural, aquatic
habitat-friendly grade control measures.
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1.3.4
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Utilize neighborhood-based flood
detention solutions.
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1.3.5
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Restrict hillside development.
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1.3.6
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Evaluate the effects of BMPs on
volume & velocity of storm water.
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Restoration
Goal 2: Better Manage,
Optimize, & Conserve Water Resources While Improving Water
Quality
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2.1
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Improve
quality of surface water for aquatic habitat and human contact.
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2.1.1
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Implement BMPs to mitigate water
quality pollutants flowing into the Arroyo Seco.
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2.1.2
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Develop
source protection measures.
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2.1.3
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Reduce
non-point sources of pollution.
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2.1.4
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Develop
ongoing water quality monitoring programs and public education of
water quality issues.
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2.1.5
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Monitor
and clean out pollutants that accumulate in non-structural BMPs.
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2.1.6
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Evaluate
existing point-sources of pollution for monitoring compliance on a
regular basis.
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2.2
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Restore the
quality and quantity of water recharge to the Raymond Aquifer.
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2.2.1
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Increase permeability of developed
land uses through implementation of BMPs such as redirecting
runoff into bioswales, removing unneeded concrete and asphalt.
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2.2.2
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Manage
groundwater to prevent future overdraft.
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2.2.3
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Mitigate
water quality pollutants percolating into the groundwater.
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2.2.4
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Test the
feasibility of recharging the groundwater basin with surface flows
in the channel through Hahamongna Basin.
Requires a detailed monitoring program and cooperation by
groundwater users.
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2.2.5
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Develop
detailed water budget to assess current inputs and outputs of
rainfall, imported water and groundwater for the hydrologic cycle
of the watershed. One purpose includes assessing the potential
overdraft of groundwater.
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2.2.6
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Promote
program that encourages all property owners to take responsibility
for retaining 50% of the “first flush” of storm water or
similar benchmark onsite.
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2.3
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Develop
groundwater management strategy for optimum use of local water
resources.
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2.3.1
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Expand conjunctive use of groundwater
basin for enhanced storage during wet periods for use during dry
periods.
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2.3.2
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Preserve foothill open space to
protect percolation into the groundwater basin and to prevent
aggravated runoff.
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2.4
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Reduce
dependence on imported water.
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2.4.1
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Increase
groundwater percolation through BMPs.
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2.4.2
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Promote
comprehensive conservation programs and best management practices
throughout the watershed to reduce water consumption.
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2.4.3
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Develop upper hillside watershed
reforestation and revegetation programs to improve local
retention.
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2.5
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Reinstate
sediment transport.
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2.5.1
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Control erosion & manage
sedimentation in restored streams (e.g., bank regrading and
revegetation, channel grade control structures, riprap), and under
bridges & freeway overpasses.
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2.5.2
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Implement BMPs for construction and
existing land uses to reduce and manage sedimentation from human
disturbance.
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2.5.3
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Conduct a
detailed hydraulic and geomorphic investigation of channel
conditions with respect to erosion potential.
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2.5.4
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Establish
a maintenance and management program to either trap the sediment
in areas where it can be easily processed or to promote its
passage through Devil’s Gate reservoir and dam downstream.
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2.5.5
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Develop
re-vegetation programs and BMPs where appropriate to reduce
erosion.
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Restoration
Goal 3: Restore,
Protect and Augment Habitat Quality, Quantity and Connectivity
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3.1
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Restore and
protect missing linkages of fragmented habitat.
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3.1.1
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Allow Rainbow Trout / Steelhead
passage from upper watershed to Glendale Narrows.
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3.1.2
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Provide and protect habitat corridors
linking the San Gabriels to the Verdugos to the San Rafaels to Mt.
Washington to Debs Park to Elysian Hills through smaller linkages
between upland and lowland zones, and from habitat patches to
waterways need to be established.
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3.1.3
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Enhance habitat linkages through the
creation of new urban stream corridors.
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3.1.4
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Plant linear urban forest
streetscapes for urban habitat connectivity.
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3.1.5
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Facilitate
and monitor terrestrial habitat connectivity from San Gabriel
Mountains to Santa Monica Mountains.
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3.1.6
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Facilitate
and monitor wildlife movement among fragmented habitats of the
watershed and the Arroyo Seco.
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3.2
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Integrate
fire management into native vegetation zones.
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3.2.1
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Implement fire management techniques
in urban interface zones.
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3.2.2
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Develop
fire management strategy, especially in areas that have not
experienced burns in over 30 years.
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3.3
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Restore,
protect and augment terrestrial species habitat in existing open
space of foothills and floodplains.
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3.3.1
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Protect and restore habitats,
processes and ecological relationships supporting sensitive and
endangered species, including arroyo toad, western pond turtle and
other focal species.
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3.3.2
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Key species to target for restoration
include Lesser Nighthawk, Greater Roadrunner, California Quail,
Bobcat, and Gray Fox.
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3.3.3
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Promote
watershed and habitat consciousness, and appropriate actions among
residents, agencies and businesses in the watershed, including
urban forestry, historic native plant distribution overlay.
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3.4
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Enhance and
strengthen the urban interface zone.
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3.4.1
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Reduce negative effects of exotic
plants and animals on native habitat.
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3.4.2
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Develop
management guidelines for buffer and edge zones.
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3.5
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Restore and protect terrestrial
species habitat in the riparian zone.
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3.5.1
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Naturalize stream and floodplain to
provide viable riparian and aquatic niche opportunities while
providing required level of flood hazard mitigation.
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3.5.2
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Restore native understory components
of existing riparian and other woodlands.
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3.5.3
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Seek creation of new niche
opportunities through biological storm water treatment systems and
restoration of watershed-supporting native plant communities –
combining habitat with water resource protection.
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3.5.4
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Restore and protect riparian
vegetation communities such as alluvial fan sage scrub and
sycamore-alder woodland.
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3.5.5
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Key species to target for restoration
include the Arroyo Toad.
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3.5.6
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Develop
exotic pest plant and animal management strategy for the
watershed.
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3.6
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Restore
aquatic species habitat.
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3.6.1
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Augment and restore missing species
from endemic plant communities.
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3.6.2
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Key species to target for restoration
include Southern Steelhead Trout.
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Restoration
Goal 4: Improve
Recreational Opportunities and Enhance Open Space
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4.1
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Improve
connectivity and public access from the Angeles National Forest to
the coastal shore.
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4.1.1
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Improve the network of trails
and open spaces with multi-modal trails.
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4.1.2
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Provide access for public use
of the watershed’s rivers and streams.
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4.2
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Protect and interpret natural,
community, cultural and historic resources.
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4.2.1
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Improve connectivity between
parks, open space, cultural and historic resources through trails
and land acquisition.
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4.2.2
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Develop trails that connect
residents across communities to meaningful destinations.
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4.3
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Integrate
natural resources management with recreational needs.
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4.3.1
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Manage parks and other open
spaces, including golf courses, trail connections and native
habitat to benefit flood management.
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4.3.2
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Provide opportunities for a
range of recreational activities.
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4.3.3
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Coordinate
between agencies and groups to meet community needs for recreation
with agency priorities.
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4.4
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Protect existing open space while
augmenting open space network.
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4.4.1
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Inventory existing and potential open
spaces for protection, recreation, land use conversion.
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4.4.2
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Introduce the concept of long-term
acquisition with an open public process.
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4.5
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Improve
visual quality of the landscape.
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4.5.1
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Expand urban tree-planting programs.
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4.6
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Mediate
conflicts between recreation and conservation and opposing
recreational users.
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4.6.1
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Improve the cooperative spirit among
recreational users through an open public process.
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