Land Use Impacts
By 2030, minimize the negative impacts of land use on the natural environment and people, while enhancing the livability of the built environment.
Land conversion and construction
practices across Hawai‘i have a significant impact on the environment,
including water quality, air quality and soil erosion. Mitigating the effects
of these impacts can conversely create more livable communities and generate a
healthier, better quality of life. An important component of this target is to
track progress toward reducing impacts on natural ecosystems by focusing new
development in the existing urban zone. This will measure increases in urban
density and subsequent reduction in land conversion of green spaces and
agricultural land, while enhancing livability within urban areas and urban
clusters. There are two classifications under the US Census Bureau for urban
land: urbanized areas and urban clusters. Urbanized areas are well understood
by most, and are defined as lands zoned as “urban” with populations above
50,000 people. The 3 urbanized areas in the state are Kailua (Honolulu County),
Kahului (Maui County), and Urban Honolulu which stretches from Hawai‘i Kai to
Makaha (DBEDT). Urban clusters, including Kalaheo on Kaua‘i and Captain Cook on
Hawai‘i Island, are defined as population centers over 2,500 but less than
50,000, and also are accounted for under the urban land zone (DBEDT). Some of
the gaps and opportunities in land use relate to the key role of planning and
permitting.
Following general trends of
population increase in Hawaii, urban density is measured to track where this
population is residing. This is not to encourage an increase in population, but
to encourage densification rather than sprawl. Urban density is balanced by
tracking park acreage per capita in the Open, Public, and Green Spaces target to
show that urban areas maintain green spaces which contribute to increased
health and livability in urban areas.
Urban Density
Urban
density is a common tool used by planning practitioners and researchers for
gauging regional land use patterns. By tracking the statewide population
compared to the total acres designated under the urban districts by the state
Land Use Commission, urban density can be tracked over time based on changes in
both population and urban land acreage, which includes both urbanized areas and
urban clusters.
Figure 1: The bar graph expresses urban density by showing the statewide proportion of people per acre of land designated as urban (both urbanized areas and urban clusters).
Source: Department of Business, Economic Development and Tourism (DBEDT) and University of Hawai‘i Economic Research Organization (UHERO)
Figure 2: The line graph shows the year to year percentage change in residential population statewide. The data can be used as a reference point for urban density increases over the same time period. Based on this data, the major increases in population density over the past 15 years do not correlate with percentage increases in population, which reflects a gradual year to year increase during this time frame.
Source: University of Hawaiʻi Economic Research Organization (UHERO) and Department of Business, Economic Development & Toursim (DBEDT)
Water Quality
Land use has a major impact on water sources across the
state, primarily through changes in land cover. Development patterns and design
choices impacting land cover include levels of impervious surface, impacting
sedimentation rates and non-point source pollution. Strategies to mitigate
theses negative impacts often include low impact development and green
infrastructure, such as bioswales, rain catchments, urban forestry and
permeable pavement. Land use impacts on water quality has a direct connection
to overall health for communities as well. By mitigating water pollution from
non-point source run off affecting streams and marine conditions, communities
can address health concerns to improve wellbeing and quality of life for
everyone.
Statewide
Brown Water Days
Figure 3: The bar graph illustrates the total number of Brown Water Days as reported by the Department Health as public advisories indicating water quality could be harmful to personal health. Various factors could can cause brown water advisories and typically result from water runoff into streams and ocean bodies.
Source: Department of Health
Figure 4: Water Monitoring Locations (Source:
Department of Health)
Statewide Water Quality Standards
Figure 5-9: These maps highlights the water quality standards for both streams and near-shore ocean water based on Department of Health indicators per island. Source: Department of Health--Clean Energy Branch
Streamflow and Baseflow Conditions
Healthy streamflow and base flow (groundwater discharge to streams) in Hawai'i are critical elements of the water cycle. Streamflow recharges groundwater which maintains thriving ecosystems and drinking water, and baseflow is the groundwater contribution to stream flow. In the past century, there has been a decrease in both streamflow and baseflow by over 20%. This shift may affect long-term climate change and land-cover factors.
Figure 10: Trends in streamflow in Hawaii, 1913-2008. Trendlines shown in a solid line indicate a
significant decrease while dashed trendlines are less significant.Source: US Geological Survey
Figure 11: Trends in baseflow in Hawaii, 1913-2008. Trendlines shown in a solid line indicate a
significant decrease while dashed trendlines are less significant. Source: US Geological Survey
Impervious Surfaces
Continued development causes an
increase in impervious surfaces across the state of Hawaii. This inhibits the
ability for watershed run-off to be absorbed into groundwater and increases
non-point source pollution run-off and the urban heat island effect.
Impervious
surfaces across Hawaii are captured in the map below in shades of pink. Note
that the source data did not provide a legend.
Impervious Surfaces across Hawai'i
Figure 13: Impervious surfaces
across Hawaii; Source: USGS The National
Map (nationalmap.gov)
Open Space and Land Use
Figure 14: The bar graph expresses urban land use for each county by showing the proportion of people per square mile of land designated as urban (both urbanized areas and urban clusters).
Source: Department of Business, Economic Development and Tourism (DBEDT)
Land Use Commission Map
The map to the right displays the land use districts and boundaries across the Hawaiian Islands. Users can zoom in closely to the interactive map to view State Land Use Districts ranging from agriculture, conservation, rural, and urban areas within each county.
Source: State Land Use District
Learn More and Make a Difference
- Current warnings and water quality advisories can be found through the Department of Health: http://emdweb.doh.hawaii.gov/cwb/wqd/viewer/
- To learn more on innovative building design and development that could reduce the impact on land use, the Living Building Challenge is a certification program to meet comprehensive green building standards https://living-future.org/lbc/
- More information on Hawai‘i’s water quality standards, follow the links to the Department of Health Clean Water Branch: http://health.hawaii.gov/cwb/site-map/clean-water-branch-home-page/water-quality-standards/
- Get involved in advocacy by participating in the Hawai‘i Chapter of the Urban Land Institute: http://hawaii.uli.org/events/