A hotel chain would like to build a new beachfront hotel along a north-south- trending stretch of beach where a strong longshore current flows from south to north. The neighbor to the south has constructed an east-westtrending groin on the property line. Will this groin pose a problem? If so, what solutions could the hotel try?

Longshore currents are the movement of water along the shore that is generated by waves breaking at an angle to the shoreline. These currents transport sand and sediment along the coast, causing erosion and deposition. A groin is a structure built perpendicular to the shore that disrupts the natural flow of the longshore current, trapping sediment and sand on one side while starving the other side of the beach.

As the longshore current flows from south to north, the east-west trending groin constructed by the neighbor to the south will trap sand and sediment on its northern side, which is the side of the neighbor's property. This will cause the beach on the southern side of the groin (the proposed location for the new hotel) to be starved of sand and sediment, leading to erosion and a gradual loss of beach area.

Yes, the groin poses a problem for the proposed hotel construction. The northern side of the groin will accumulate sand and sediment, creating a wider beach for the southern neighbor, while the southern side (where the new hotel will be built) will experience erosion and beach decline due to the disruption of the longshore current.

1. Collaborate with the neighbor: One solution is for the hotel chain to collaborate with the neighbor to jointly reconfigure or remove the groin to mitigate its impact on the longshore current and allow for more equitable sand distribution between the properties. 2. Construct an additional groin: The hotel chain could build another groin on their property, north of the existing groin. This would restore the balance in sediment distribution and protect their beach from erosion. However, this may affect the properties further north and could lead to legal or environmental issues. 3. Beach nourishment: The hotel chain could periodically replenish the beach by importing sand and sediment from another location. This will counteract the erosion caused by the longshore current being disrupted by the neighboring groin, but might be costly and could have environmental consequences. 4. Construct a breakwater: A breakwater is another option, which is a structure built offshore to dissipate wave energy and protect the shoreline from erosion. This could minimize the impact of the longshore current on the properties and reduce erosion. However, breakwaters can also cause shifts in beach dynamics, affecting neighboring properties, and can have environmental impacts.