how does stormwater effect beach erosion/loss of sediment on shorelines?
Read many of these and study the photos and other images:
http://www.google.com/?gws_rd=ssl#q=beach+erosion+after+storms
There's a great deal of information in these articles.
OKE
Stormwater runoff can contribute to beach erosion and the loss of sediment on shorelines in multiple ways:
1. Increased Flow: During rainfall events, stormwater runoff can enter rivers, streams, and creeks, which then discharge into the ocean or other bodies of water. The increased flow of water can lead to higher wave energy and stronger currents, which erode the beach and wash away sediment. These higher flows can remove sand from the beach, depleting the sediment available to replenish eroded areas.
2. Sediment Transport: Stormwater runoff can carry significant amounts of sediment, debris, and pollutants from urban areas, construction sites, and other disturbed landscapes. As the runoff reaches the shoreline, it can deposit these sediments in coastal waters, reducing the clarity and quality of the water, and potentially smothering the beach ecosystem. Sediment transport can disrupt the natural balance of sand deposition and removal, further exacerbating erosion.
3. Altered Hydrology: Urbanization and the paving of surfaces increase stormwater runoff volumes, speed, and intensity. As a result, the natural hydrological cycle is disrupted, and less rainwater infiltrates into the ground. This reduction in infiltration leads to reduced groundwater recharge, which can contribute to shoreline erosion. Groundwater often serves as a vital source of fresh water to support vegetation and maintain sediment stability along coastlines. When groundwater levels drop due to reduced recharge, it weakens the beach's ability to maintain sediment.
To mitigate the effect of stormwater on beach erosion and loss of sediment, various management practices can be implemented. These include:
1. Coastal Engineering: Constructing structures like groins, jetties, and breakwaters can help control the flow of water and sediment along the shoreline, trapping sand and reducing erosion. However, these structures can have their drawbacks and impacts on adjacent beaches.
2. Beach Nourishment: Adding sand to replenish eroded areas can help restore the natural sediment balance and stabilize the beach. Beach nourishment projects involve importing sand from offshore or other sources to rebuild the beach profile.
3. Stormwater Management: Implementing effective stormwater management strategies, such as green infrastructure practices and the use of permeable surfaces, can help reduce the volume and velocity of runoff. This promotes infiltration, groundwater recharge, and limits sediment and pollutant transport to coastal areas.
4. Land-use Planning: Implementing adequate land-use planning and regulation can help prevent excessive development near shorelines and identify appropriate setbacks that protect natural coastal processes. This can help maintain healthy beach ecosystems and reduce the impact of stormwater runoff on erosion.
In conclusion, stormwater runoff affects beach erosion and loss of sediment by increasing flow, transporting sediment, and altering hydrology. Implementing coastal engineering projects, beach nourishment, stormwater management, and land-use planning are some strategies to mitigate these impacts.