CLIMATE CHANGE WILL INTENSIFY HEAT AND FLOODS AROUND THE PARK

D.W. FIELD PARK MAY BE AN IMPORTANT CLIMATE ADAPTATION TOOL FOR BROCKTON

Massachusetts’ State Hazard Mitigation and Climate Adaptation Plan identifies the most important climate hazards for Brockton and the surrounding region as “changes to temperature extremes, changes in precipitation patterns, and consequent changes in the patterns of river flows that can lead to inland flooding” (RS46).

Heat and flooding are already issues the city is managing, and climate change will only exacerbate these challenges. Bolstering green spaces like D.W. Field Park could be a critical strategy for increasing climate resilience in Brockton.

Extreme Temperatures

Impervious Surfaces

35%, or 4,825 acres, of Brockton is covered in impervious surfaces, which degrade water quality when runoff from them is not treated and trap heat in the city.

Impervious surfaces like roads and roofs disrupt the natural water cycle by blocking precipitation from infiltrating where it falls and by warming and concentrating runoff. This increases the temperature, sediment, and pollutant loads washing directly into rivers and lakes or storm drains that eventually convey runoff into water bodies. These pollutants harm the health of aquatic ecosystems (NOAA).

Impervious surfaces also interrupt the earth’s natural heating and cooling processes. They absorb and store heat from the sun more intensely than natural materials like soil, water, or trees. Highly paved areas heat up more intensely during the day and aren’t able to cool down adequately at night.

This is called the Heat Island Effect and can cause serious health problems, especially for the young and the elderly.

Tree Canopy

37% of Brockton, or 5,200 acres, is covered by tree canopy. D.W. Field Park hosts 405 acres, or 8% of the city’s trees. Trees provide a range of benefits to cities, improving water quality, managing stormwater, and regulating the temperature of the landscape.

Trees roots and the soils they grow in act as a natural water filter, absorbing pollutants like excess nutrients and heavy metals before they flow into lakes and streams instead of channeling untreated water directly the way storm drains do. Trees can also absorb or break down some of the heavy metals, chemicals, and oil that come off roofs and roads (North Carolina Forest Service).

Forested areas mitigate flooding by slowing and infiltrating water during heavy rainfall before it reaches streams and rivers (Lyons and Gartner).

Trees cool cities by providing shade and adding moisture to the air through a process called evapotranspiration. The cooling impacts of trees can be especially powerful in areas of dense canopy coverage like parks, bus stops, and school yards, and are frequently regarded as an important climate adaptation tool in dense urban environments (Alberti et al.).

Surface Water

Not much of Brockton’s original surface water remains. Many of the brooks and rivers in the city flow through underground pipes and culverts for long stretches and are not accessible to or known of by residents of the city (OSRP 22). Several large ponds have been filled or drained to accommodate construction or due to contamination (OSRP 23).

Today, 204 acres of Brockton are covered by water, and D.W. Field Park contains most of that: 178 acres, or 87%.

Open water is a critical resource for human and nonhuman species alike. Water cools the environment around it, and provides important habitat for a range of creatures. Surface water quality is declining, however, as water temperatures increase with climate change and high-intensity rainfall events continue increasing in frequency; these storms mobilize more pollutants than moderate rain events, further contaminating surface water (U.S. Climate Resilience Toolkit).

Since D.W. Field Park encompasses most of the remaining surface water in Brockton, this is an important place to protect and enhance water quality.

By as early as 2030, the summer mean temperature could increase by 3.6 degrees Fahrenheit from the 1950-2013 historical period (RS46), increasing heat-related health risks and the need for ways to cool down in the summer. Brockton is already feeling the impacts of hotter summers. In 2018, the city opened cooling centers and extended the hours of municipal pools in order to help residents manage the heat (OSRP 42).

As summer temperatures continue to rise, D. W. Field Park’s shady, forested environment has the potential to serve as an additional cooling resource for residents on hot days.

Flooding

By mid-century, the 1 percent annual chance of river flood ing could be two times more likely to occur (SHMCRP, RS46). The combination of high impervious surface coverage paired with an aging city-wide drainage system mean that even moderate rainstorms can cause floods in Brockton (OSRP 41). Salisbury Brook south of the park has been a site of especially problematic flooding.

As a forested area that drains to Salisbury Brook, D.W. Field Park may be able to play a role in mitigating flooding downstream.