Discussion of Marine Streets—A Living Marine Edge

It is very exciting to see someone thinking about changing the way we build waterfront streets. For years, civil engineers have been covering our land with impervious surfaces, such as roadways and parking lots. Many of these roads and parking areas are directly connected to the local waterways, meaning that every drop of rain that lands on these surfaces flows directly into the river without any level of treatment or any opportunity to infiltrate. Under the auspices of protecting human life, these same engineers proceeded to fence off the natural wetlands at the end of these waterfront roads, limiting human access to these natural systems. The vision that Ms. Wilks presents in her paper is a holistic approach to improving water quality, enhancing ecological conditions, and providing a strong social interaction between the people of the city and their river, all as part of changing the way we build waterfront streets.

The three concept designs that Ms. Wilks presents: 1) Sloped Street; 2) Park Marine Street; and 3) Mixed Street in their own way improve city ecology, water and air quality, and habitat while enhancing the public’s ability to interact with the river. There will be several issues in converting these concepts into actual designs. The first issue is the ability to use pervious surfaces and bioretention systems to infiltrate and treat stormwater runoff in this setting. As one approaches the river, the groundwater table approaches the surface. It will be difficult to infiltrate stormwater runoff if the groundwater table is too high. These systems can still function as treatment systems if an impermeable liner and an under-drain system are installed to minimize the interaction between the high groundwater table and the stormwater runoff being treated by the pervious pavement or bioretention systems. The impermeable liner would be placed at the bottom of the system to prevent the groundwater table from entering the under-drain system that would be installed on top of the liner. The soil placed over the under-drain system would provide treatment of the stormwater as it infiltrates from the surface through the soil and into the under-drain system.

The second issue is the materials being used for these Marine Streets. Pervious pavements have typically been porous concrete, pervious asphalt, or paving stones where the stormwater passes through the seams between the stones. It is unclear how these materials will perform in the type of environment to which these Marine Streets will be exposed. These systems will be continuously exposed to saltwater and/or regularly inundated during high tide and storm events. This exposure might limit the life span of these materials.

The final issue is public safety. The natural flow of people from the community to the living resource of the river and its associated environment is a great benefit of the Marine Streets systems being proposed by Ms. Wilks. In providing people these opportunities, we still need to ensure their safety. Mechanisms will be needed to ensure vehicles will not accidentally drive into the river. When pavement gets wet, it can be slick and a slipping hazard. When people are allowed to have direct access to the water, there is always a hazard of people falling into the water. Ensuring people’s safety needs to be an important consideration when moving Ms. Wilks’ concepts to final designs.

Ms. Wilks has presented an outstanding vision for the marine streets of the future. The concepts she has presented in her paper are visionary but will need a multi-disciplinary team of professionals to take them into final designs. The Marine Streets that Ms. Wilks has proposed can improve the ecological conditions, social engagement with the environment, and water and air quality.