Shoreline Erosion

Shorelines are among the most productive environments with majority of the lake life, from microorganisms to birds being dependent on the shore for their survival.  Erosion occurs when soils along the shoreline are weathered away because of a variety of factors such as: the composition of the beach, lake water levels, the amount of precipitation and presence of vegetation. It is important to note that erosion and deposition of shorelines are natural processes, but the rate at which they happens are largely affected by changes in the land use. Sand is more easily erodible, and the dominant soil type found in our project site of the Hamilton Beach Strip. The Hamilton Beach is bustling with human activities that have accelerated the rate of erosion. High foot traffic, impervious surfaces causing runoff, and lack of native vegetation are few contributors to shoreline erosion along Lake Ontario. Our goal is restore the natural shoreline to prevent erosion of the sand dunes presently found there that lack in native vegetation and stabilization.

How do sand dunes form and why are they important?

In simple terms sand dunes are piles of sand that are formed when fine particles such as sand  are transported onto the beach by both wind and wave. They are constantly undergoing a cycle of erosion and build up, but the level of severity can be dependent of what lives in the sand. With the presence of native vegetation such as dune grasses the fine particles of sand are caught among them and the loss of sand is lessened. When the roots take place and the grass spreads by rhizomes it creates a strong hold on the sand surrounding it; as water levels change and waves occur they bring in more particles to build up the dunes. 

Benefits of a Natural Shoreline

Natural Shoreline.pngA naturally vegetated shoreline improves the water quality of the body of water it runs along by absorbing and trapping runoff. As runoff of rain or melted snow runs along the ground it picks up pollutants such as fertilizer, animal feces, trash, and salt. All of these pollutants that have negative effects on the water quality are retained, filtered and treated by vegetation before it reaches the water.

If extra sediment is being taken off shore and into the water it can cause problems for the aquatic life. One species affected by excess sediment are fish whose spawning beds become covered or wiped out. On shore, the vegetation provides habitat for various plants and animals. If the conditions are right for plants to establish, those plants will encourage a number of species of animals to use the vegetation for shelter, food and a safe travel corridor.

For coastal properties sand dunes are essential because they are the buffer for everything inland preventing severe erosion. Typically, native plants have a greater root depth and density and these root systems help to lock the sand and topsoil in place from being washed away into the lake. When storms like those Hamilton experienced in late April and early May 2017 which ended in higher than normal lake levels, sand dunes prevent erosion along the properties by the shore like the houses of the Hamilton beach community.

Problems of erosion in Hamilton

Beach Poplar Roots.JPGThe whole city of Hamilton have been witnesses to the flooding and
problems that arose in late April and early May 2017. In combination with the changes in wind pattern there is a change to the wave patterns and energy that are hitting the shores. The Hamilton Beach Community and the Waterfront Trail had taken quite the hit with large portions of the beach being submerged in water or washed away where dense vegetation was lacking.

Not only are the changes in climate causing the increased temperature which leads to changes in wind pattern but there is a significant increase in debris pollution. For example, the Hamilton  sewage treatment facility, but there had been so much rain that there was an overflow of the sewage plant and storm sewers that brought out products that were unnecessarily flushed down residents toilets. Some of these products include used tampons, applicators, condoms and even needles.

The areas of concern were those that lacked native vegetation, that provides the stability for the loose sands that make up the dunes and shores. With the overall increase in weather patterns and wind speeds there is a larger impact of erosion along the shores unless conservation measures are put into action.

Hamilton Beach Strip Restoration Plans

Environment Hamilton and the Hamilton Naturalists’ Club with the help of the City of Hamilton and Hamilton Conservation Authority are working towards restoring 151 metres of shoreline, this total is a cumulative measurement of different sections along a stretch of the beach that are of high concern for erosion. Our main goal is to plant a minimum of 3000 plants, with a large portion being native dune grasses. The grass that we are planting is marram grass (Ammophila breviligulata). It is used along the Great Lakes as a stabilizing agent for sand dunes, erosion control and revegetation. Considered a pioneer plant, marram grass is one of the first plants to establish in a disturbed area such as our eroded zones and as it grows provides a suitable environment for other plant species to establish.

Hutches School Field Trip Planting

Hutches Pre Planting.JPG

Hutches on the Beach is an iconic beachside hangout, famous for their fish and chips or their ice cream but the beach that sits outside lacks native vegetation making it prone to erosion. The section we are most concerned with on the northwest side of the building where there is no vegetation at all (see photo). Prior to our student field trip we fenced the area because of the high foot traffic around Hutches; although Marram grass has numerous characteristics that make it a top choice for dune and shoreline restoration, it does not tolerate if trampled. Our post planting photos are a great example of how small and unnoticable the initial grasses are, without the fence the likelihood that they would be trampled is significantly higher. 

Hutches Planting After.JPGOn June 16, we had St. Marguerite d’Youville Catholic Elementary School come out to plant 500 Marram grasses. We spent the morning putting the grass plugs in the sand or cleaning up garbage around our site. The students were super excited and so were we to spend a sunny and breezy day down by the lake. Planting took little effort because the sand left little need for hard digging and by noon all the grasses were planted and the fence and signs were up. Thanks to the kind employees at Hutches for providing the class with free ice cream for all their hard work!

 

Dexter Avenue

Along the shore of Lake Ontario, running along Beach Boulevard there are sections of low to high priority based on the factors of vegetation, present erosion, invasive species, and encroachments. Of all the sections of concern the portion of beach that is found at the end of Dexter Ave is one of the more eroded areas. As photographed below, the two photos are of the same section of beach at the end of Dexter Ave and only a few weeks apart. At the end of April 2017, here in Hamilton we experienced a month worth of rainfall in a matter of a couple days and this amount of water caused the banks and dunes that lacked native, deep-rooted vegetation to wash away with the wind and waves. Since the grasses that are presently there are non-native and shallow rooted, they too would have eventually begun to wash away or get undercut if preventative measures are not taken. The City of Hamilton re-adjusted the snow fencing at the site as a means of catching sand that came back in as the storms passed, because of that simple placement our native dune grasses have sand to be planted into and grow. 

Beach Dexter Ave 1.jpgBeach Dexter Ave 2.JPG
For this site we will be planting a minimum of 3000 plants, which will be a combination of marram grass and common milkweed (Asclepius syriaca). With original plans to have everything in the ground by mid-May, the large scale rainfall, eroded banks, and amount of debris brought to shore caused the planting event to be postponed until the September 2017. 

Come out and volunteer!
Saturday, September 16th from 10am-12pm 
Planting along the waterfront trail, where it meets Dexter Ave
Park along Beach Boulevard
Please bring gloves, shovels/trowels if you have them
Snacks are provided! 
Email Diana at dgora@environmenthamilton.org for any additional questions. Hope to see you there!

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