Planning for a Resilient Haddonfield
An analysis of the climate change-related hazard vulnerabilities in Haddonfield, to inform the update of the town's forthcoming Master Plan.
Background
In 2021, Governor Murphy sanctioned legislation (P.L. 2021, c6) mandating the inclusion of a Climate Change-Related Hazard Vulnerability Assessment in Municipal Land-Use Law. This requires all New Jersey municipalities, including Haddonfield, to integrate CCRHVA into their Master Plans.
The steps involved in the CCRHVA are outlined in the graphic below.
The Haddonfield CCRHVA and this StoryMap
Haddonfield Borough, in collaboration with Pennoni Associates, is updating its 1984 Master Plan, with a slated release in 2024. The forthcoming plan will include the Climate Change-Related Hazard Vulnerability Assessment (CCRHVA), evaluating vulnerabilities to climate-induced hazards like flooding, extreme heat, and precipitation.
The StoryMap, prepared under the Rutgers New Jersey Climate Corps* program, gives an overview of key demographics in Haddonfield, before expanding upon the first step of the CCRHVA, the 'Current and Future Threats Analysis' for the borough. Specifically, it delves into the vulnerability of the community to flooding, extreme precipitation and heat.
*The New Jersey Climate Corps program is a cohort of graduate-level students offering climate services under the umbrella of the New Jersey Climate Change Resource Center (NJCCRC) at Rutgers University. This StoryMap is an outcome of a partnership between the NJCCRC, Pennoni Associates and Haddonfield. The deliverables of this project inform Haddonfield and other stakeholders of potential climate change-related hazards and associated risks.
An Overview of Haddonfield
Haddonfield is a small town located in Camden County, approximately 5 miles from Philadelphia. It spans across three square miles, with its 17 drainage areas discharging into the Cooper River and its tributaries. A map of Haddonfield with some important landmarks, along with an inset map showing the location of Haddonfield withing Camden County can be seen on the right.
Demographics (American Community Survey Data, 2021)
From 2011 to 2021, Haddonfield's population grew by 6%, reaching 12,383 in 2021. The borough has a relatively low poverty rate of 2%, and a median income of $159,323. The median age of Haddonfield is 39.6 years.
About 31% of the workforce is engaged in education, healthcare, and social assistance. Major employers are part of the service industry, providing various professional, scientific, and administrative services. Finance, insurance, and real estate are also important employers. Notably, over 79% of residents hold at least a Bachelor's degree.
Land-Use
Around 90% of Haddonfield consists of developed land, primarily used for single-family residential housing. The second most prevalent land-use is commercial, followed by school and school property.
Land-Use | # of parcels |
|---|---|
Residential (2) | 4,112 |
Apartment (4C) | 12 |
Commercial (4A) | 279 |
School and School Property (15A, 15B, 15C) | 103 |
Church and Charitable (15D) | 28 |
Cemeteries and Graveyard (15E) | 3 |
Other Exempt (15F) | 40 |
Vacant (1) | 34 |
The value in parenthesis is the property class number of parcels are from the MOD-IV property tax data .
The majority of Haddonfield's housing stock (51 percent) dates back to before 1939, making it historically significant.
Housing
The majority of Haddonfield's housing dates back to before 1939, holding historical significance. In 2021, 83% of households were homeowners, with 94% of the homeowners being White.
Housing Data (ACS 5 Yr Estimates, 2021) | # |
|---|---|
Average Household Size | 2.64 |
Median Household income | $159,323 |
Median Rental Cost per month | $1,084 |
Median House Value | $558,300 |
Climate Change and Natural Hazards
Continued greenhouse gas emissions are driving global warming and climate change, causing severe, uneven, and, in some instances, irreversible impacts on people, economies, and ecosystems worldwide. In turn, the increase in global warming contributes to more frequent extreme weather events like hurricanes, storms and heat waves.
The New Jersey Department of Environmental Protection has published the following key data related to climate changed in New Jersey:
It is important to anticipate these natural hazards and implement mitigation measures to safeguard communities and assets. The upcoming sections outline Haddonfield's vulnerability to extreme precipitation, flooding, and extreme heat, utilizing NJAdapt's suite of datasets and maps. NJAdapt covers a wide range of socio-economic and environmental data which is used for modeling climate change-related hazards.
Extreme Precipitation
Extreme precipitation is said to occur when rainfall or snow exceeds the normal amount for a specific location. Climate change is expected to increase the frequency and intensity of extreme rainfall events, leading to more frequent and intense flooding.
After an extreme rainfall event, the risk of waterborne disease outbreaks increases. Additionally, homes may suffer water damage and mold, impacting indoor air quality and potentially exacerbating conditions such as asthma and other respiratory illnesses.
Residents canoe through floodwater in the aftermath of Hurricane Ida in Manville, New Jersey
In New Jersey, the likelihood and magnitude of extreme rainfall events is projected to increase, in all emissions scenarios.
...But what exactly are emissions scenarios?
Emission scenarios and Representative Concentration Pathways
Emissions scenarios are potential trajectories for concentration of greenhouse gases.
In this StoryMap, we use Representative Concentration Pathways (RCPs), which are emissions scenarios prepared and adopted by the Intergovernmental Panel on Climate Change (IPCC).
Specifically, RCPs are four potential trajectories projecting the concentration of greenhouse gases and air pollutants until 2100. RCPs are prepared by considering diverse factors such as socio-economic indicators like population growth, technological advancements, and climate policies aimed at mitigating greenhouse gas emissions. The four trajectories or scenarios are outlined below:
This picture shows the 4 different RCP trajectories. The highest pathway, or RCP (8.5) assumes an uncontrolled growth in greenhouse gas emissions throughout the current century, while the lowest pathway RCP (2.6) assumes that emissions peak between 2010 and 2020, and subsequently decline. RCP and RCP 4.5 are moderate emissions pathways.
Projected Precipitation in Haddonfield
The table below from the NJ Climate Navigator shows the inches of rainfall projected to occur in Haddonfield for different storm events during a 12-hour period for both a historical baseline and under a moderate emissions scenario (RCP 4.5) and a high emissions scenario (RCP 8.5), respectively.
*Rainfall is measured in inches.
Analysis
Both the moderate emissions scenario and the high emissions worst-case scenario project an increase in rainfall compared to the baseline for storm events with varying likelihoods. For a storm event with a 50 percent chance of occurring, the projected rainfall in inches rises from the 3.30 inches baseline to 3.50 in mid-century for the moderate emissions (RCP 4.5) scenario and to 3.63 inches in the mid-century for the high emissions (RCP 8.5) scenario.
In both trajectories, it further increases in the late-century and this trend continues for more intense storm events as well. In other words, storm events of greater magnitude, which are less likely to occur (e.g., a storm event with a 1% chance), also exhibit the same trend of increasing precipitation for both scenarios in the mid and late twenty-first century. As a result, New Jersey is at greater risk of flooding.
Flooding
Flooding is the second most fatal weather-related hazard in the U.S. Urban areas are often more susceptible to flooding compared to rural areas or suburbs due to the prevalence of impervious surfaces. These surfaces hinder water absorption into the ground, leading to runoff.
Flood Events
Climate scientists commonly project floods in terms of 'flood events,' using statistical probability to determine the likelihood of floods of varying magnitudes. Flood events of higher magnitude have a lower probability of occurrence.
With climate change, the 100-year and 500-year flood events are increasingly utilized in preparing flood mitigation and adaptation strategies. These events represent less frequent, high-magnitude floods with the potential for widespread damage to life, health, and assets.
- 100-Year Flood Event: Signifies a 1 percent annual probability, meaning a 1 out of 100 chance of occurring in any given year. Hurricane Ida, shown in the radar imagery on the right, was a 100-year flood event.
- 500-Year Flood Event: Signifies a 0.2 percent annual probability, with a 1 out of 500 chance of occurring in any given year.
While these flood events represent floods with a 1 in 100 or 1 in 500 chance of occurring in a given year, climate change projections indicate an increased likelihood even for these less frequent, high-magnitude flood events. This has led to headlines and articles highlighting the heightened vulnerability of the New Jersey and New York to flooding, such as those as shown below.
Tax parcel-wise flood risk
In the right window, two maps highlight tax lots which are susceptible to flooding during the 100 and 500-year flood events, within a moderate emissions trajectory*.
You can use the slider to toggle between the maps showing 100 and 500 Year events.
*The moderate emissions trajectory, corresponding to RCP 4.5, represents a middle-ground scenario, indicating intermediate efforts in mitigating greenhouse gas emissions. Under this scenario, emissions peak around 2040 and subsequently decline. Essentially, RCP 4.5 aligns with future emission levels consistent with current global policies aimed at reducing emissions.
Value of damaged properties
For each property class, the table below presents the total area of flooded parcels for each land-use, along with the total value of improvements and land. Improvement values represent the worth of physical structures on the property, while land values signify the value of the land itself.
While not all structures (improvements) may necessarily be damaged during a given flood event, especially considering the location of the improvement within the tax parcel, estimating the total damage value in dollars is helpful in projecting the potential fiscal impact on the municipality. This enables the community to be prepared for a given flood event.
100-Year event
Property Class | # Parcels Flooded (% within property class) | Area Flooded per Property Class (in acres) | Value of Flooded Land Parcels | Value of Flooded Improvement |
|---|---|---|---|---|
Residential (2) | 74 (1.7%) | 43 | $24,250,500 | $23,439,000 |
Commercial (4A) | 6 (2%) | 19 | $1,004,700 | $997,700 |
School and School Property (15A, 15B, 15C) | 21 (23%) | 136 | $34,935,200 | $5,872,500 |
Church and Charitable (15D) | 2 (7%) | 0.5 | $334,300 | - |
Other Exempt (15F) | 14 (35%) | 103 | $9,681,500 | $1,193,600 |
Vacant Land (1) | 4 (12%) | 5 | $506,200 | - |
Total | 121 (2.6% out of the total # parcels in each land-use) | 306.5 | $70,712,400 | $31,502,800 |
500-Year event
Property Class | # Parcels Flooded (% within property class) | Area Flooded per Property Class (in acres) | Value of Flooded Land Parcels | Value of Flooded Improvement |
|---|---|---|---|---|
Residential (2) | 106 (2.5%) | 60 | $33,652,900 | $30,526,200 |
Commercial (4A) | 8 (3%) | 20 | $1,445,000 | $1,006,800 |
School and School Property (15A, 15B, 15C) | 19 (21%) | 136 | $35,014,500 | $5,872,500 |
Church and Charitable (15D) | 1 (3.5%) | 0.5 | $334,300 | - |
Cemeteries and Graveyards (15E) | 1 (33%) | 1.5 | $625,500 | - |
Other Exempt (15F) | 11 (27.5%) | 103 | $9,681,500 | $1,193,600 |
Vacant (1) | 7 (20.5%) | 6.5 | $880,900 | - |
Total | 153 (3.3% out of the total # parcels in each land-use) | 327.5 | $81,634,600 | $38,599,100 |
Flash Flooding
Flash flooding occurs over relatively shorter time spans, and is often caused by thunderstorms of high magnitudes, leaving people unprepared to deal with the flood impact. The likelihood of flash flooding increases with extreme precipitation.
Within Haddonfield, there are several areas which are vulnerable to flash floods. It is concerning that some of these vulnerable areas are developed or may be developed/redeveloped according to the existing zoning provisions.
In 2023, when a thunderstorm led to flash flooding in the borough, these areas faced considerable damage, causing residents' basements to get flooded, damaging power lines and trees, and leaving commuters stranded on the streets for several hours together.
Build-Out Analysis
Similar to other urban areas, Haddonfield is predominantly developed, featuring limited open and pervious surfaces that could facilitate water seepage and help mitigate flood damage.
The window on the right displays two maps prepared by Pennoni Associates as part of the build-out analysis for the Climate Change-Related Hazard Vulnerability Assessment within the 2024 Master Plan.
- Non-Developable Areas: Clicking the arrow facing right reveals a map showing the coverage of developed and impervious surfaces, along with areas containing transportation infrastructure, water bodies, and wetlands. Crucially, it highlights in muted yellow, the areas which may not be developed under the current zoning provisions.
- Developable and Redevelopable Areas at Risk of Flooding: Clicking the left arrow and sliding towards the left unveils developed and redevelopable areas within Haddonfield at risk of flooding. This includes areas (i) intersecting with a 100-year Floodplain (violet-highlighted polygons with boundary and diagonal lines in dark violet), (ii) being within 500 feet of Flash Flooding Areas of Concern (red-highlighted polygons with boundary and diagonal lines in dark red), and (iii) Flash Flooding Areas of Concern (red-highlighted ovals).
Areas of concern
These areas are prone to flooding due to factors or a combination of factors like high volumes of runoff or tailwater surcharging from nearby water bodies or lack of adequate drainage infrastructure. Specifically, East Park Avenue in central Haddonfield, has inadequate drainage infrastructure.
Zooming in
The addresses of specific Areas of Concern, or areas susceptible to flash flooding, can be viewed in this map. These areas were identified based on historical data on flooding, along with records of locations subject to recurring flooding.
Of these areas, Haddonfield has effectively implemented flood mitigation strategies in the Avondale, Mt Vernon, and Peyton avenues and Barberry Lane areas. Furthermore, Hickory Lane, Beechwood Avenue, Ellis Street and Maple Avenue have undergone improvements for flood mitigation.
However, additional flood mitigation infrastructure is still needed in some of these areas. Pennoni Associates proposes the following infrastructure improvements and Green Infrastructure solutions for the Areas of Concern:
Problem Area | Type of Improvement (Green/ Drainage/Other) |
|---|---|
Oak Avenue | Paving/regrading |
W Cottage Avenue | Paving/regrading |
East Park Avenue | Drainage |
Park Lane | Green/regrading |
Upland Way | Drainage |
Coles Mill at Grove Street | Green |
Source: Pennoni Associates (2022), Stormwater Drainage Study and Green Infrastructure Plan for Haddonfield Borough
Green Infrastructure solutions include strategies such as replacing sidewalks with stone drainage pits, replacing asphalt pavement with pervious pavement and stone subbase and installing bio-retention systems and planting street trees which consume high amounts of water. Permeable paving and improving drainage infrastructure are also crucial to flood mitigation.
Please note that the maps were developed as part of the Stormwater Drainage Study and Green Infrastructure Plan for Haddonfield Borough prepared by Pennoni Associates in 2022. Infrastructure improvements have been undertaken by the borough since the publication of the study. Furthermore, it is strongly recommended that any future improvements are aligned with the Borough's Capital Improvements Plan.
Extreme Heat
New Jersey is warming up faster compared to the global average of 2.0°F (1.1°C) as well as the Northeast regional average of 2.7°F (1.5°C). Additionally heatwaves are projected to occur more frequently and last longer by 2050 (NJDEP, 'Climate Change and its Impacts ').
The bar chart below, illustrates the average summer temperature in New Jersey from 1900 to 2022, measured in °C. The data reveals a rise in the average annual summer temperatures from the early 1900s to 2022.
Effects of extreme heat
Extreme heat has serious effects on health, leading to more deaths. In the coming decade, due to climate change, we might see a 55% increase in deaths caused by summer heat compared to the previous 30 years (1990 to 2020).
Furthermore, extreme heat has widespread socio-economic consequences like lower farm yields and increased use of water and energy (NJDEP, 'Climate Change and its Impacts ').
Canopy Cover
New Jersey has witnessed considerable urban development with more buildings and pavement than green spaces like forests and fields. This creates the urban heat island effect, where cities retain more heat and cool down less. Increasing the green cover or canopy cover can help mitigate the impacts of high temperatures.
Much of Haddonfield is developed, having a high proportion of impervious surface coverage, making it vulnerable to heat waves. The building coverage and impervious coverage within Haddonfield can be seen in the map below, prepared by Pennoni Associates as part of the Build-Out Analysis for the CCRHVA.
However, compared to the rest of New Jersey Haddonfield also has a higher canopy cover in each land use. This contributes to reducing the community's vulnerability to extreme heat.
The canopy cover of Haddonfield compared to the rest of the state within each type of land-use category can be seen below.
Percent Tree Canopy by Urban Land Use (38.0% average), Haddonfield vs. Camden County.
The central part of Haddonfield, consisting of the PATCO Haddonfield Station with its rapid transit lines and a concentration of commercial establishments, has a high proportion of impervious surface, along with a heightened transportation activity. Consequently, as the map below shows, the Land Surface Temperature in the borough for the year 2022, is higher in the central part compared to the rest of Haddonfield.
Heat Vulnerability Index
Haddonfield's vulnerability to extreme heat can be analyzed further by looking at its Heat Vulnerability Index (HVI). The HVI, developed using the NJHazadapt tool , encompasses three groups of indicators:
- Exposure: Represents physical environmental stressors or characteristics contributing to adverse health outcomes at both individual and community levels. The sub-indicators making up the Exposure indicator are: Ratio of Impervious Cover, Annual PM2.5 Concentration, Ozone Exceedance Days and Summer Average Temperature Normals.
- Sensitivity: Indicates the extent to which individuals or communities may be impacted by extreme heat. Sensitivity sub-indicators include: Percent of Population Aged Below 5 Years, Percentage with Disability, Percentage of Homes Built Before 1960, Percentage of Population Engaged in in Outdoor Occupations, Percent Living Alone, Asthma Prevalence, Diabetes and Coronary Heart Disease Prevalence.
- Adaptive capacity: Reflects the ability of individuals or communities to respond, take action to mitigate hazards associated with extreme heat, and recover from an extreme heat event. Adaptive capacity covers: Percentage of Population Below Poverty Line, Percent Unemployed, Percent Linguistic Isolation, Percent Without High School Diploma, Percent Non-White and Percentage of Population without Health Insurance.
The live map provided below illustrates the HVI for each census tract in New Jersey. Haddonfield, with four census tracts, is outlined by a bold black boundary. Clicking on a specific census tract within Haddonfield, and elsewhere in New Jersey unveils the HVI of the census tract selected.
Analysis
Haddonfield comprises four census tracts, each ranking highest in the Exposure indicator, reflecting a higher prevalence of environmental stressors leading to higher temperatures in the borough. Following Exposure, the Sensitivity indicator takes precedence, succeeded by Adaptive Capacity. Essentially, while Haddonfield exhibits a higher Exposure indicator—representing heat stress from factors like PM2.5 or ozone concentration—compared to other indicators, the community's positive socio-economic and health characteristics mitigate its impact. Consequently, Haddonfield's Heat Vulnerability Index (HVI) is generally lower than that of Camden County, as evident in the image below.
However, the census tract in southeastern Haddonfield has a higher HVI relative to the other three tracts. Along with having a high Exposure score of 5 similar to the remaining tracts, the Sensitivity indicator is also comparatively higher the rest of the tracts. This is attributed to elevated scores in health indicators such as Asthma Prevalence, Diabetes, and Coronary Heart Disease Prevalence for this census tract. Additionally, like the other tracts, Haddonfield scores high on the Sensitivity sub-indicator of Percentage of Homes Built Before 1960, reflecting the prevalence of older structures.
Nevertheless, the good news is that overall, Haddonfield's HVI remains relatively lower compared to the broader county and New Jersey.
Conclusion
In comparison with the rest of New Jersey and the Northeastern region, Haddonfield is relatively less prone to natural hazards, in part owing to its location and extensive tree cover. However, it is crucial that the borough upgrades its stormwater system and installs the requisite green infrastructure in order to ensure that the community is able to mitigate flooding in the case of extreme storm and precipitation events. Additionally, increasing the pervious coverage specifically by expanding the canopy cover can help in mitigating not just flood impacts but also the consequences of extreme heat.
