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Black, K.P.; Kulkarni, K.B.; Naik, G.B.; Naik, M., and Mathew, J., 2021. Improving training wall orientation at river and estuary entrances. Journal of Coastal Research, 37(3), 484–493. Coconut Creek (Florida), ISSN 0749-0208. Natural river and estuary entrances adjust in response to the prevailing sedimentary and hydrodynamic environment. In India, during the monsoon rains, the ebb jet can be very large, firing water and sediments along a variable orientation to create the associated ebb deltas. However, once the entrance is trained onto a fixed alignment, this powerful jet "pump" can have adverse impacts. Due to downdrift erosion caused by the entrance training walls at the Old Mangalore Port (Karnataka, west coast of India), the breakwater was modified to reorient the ebb jet in the direction of the longshore drift. The goal was to beneficially use the natural pumping action to drive sand across the entrance without mechanical assistance. Three years of monitoring revealed improvements in downdrift beaches and navigational safety, while maintenance dredging has ceased. The entrance region has deepened by 854,166 m3 after reorienting the ebb jet over the period from October 2017 to February 2020. In contrast, the entrance shoaled by 160,305 m3 over the period from September 2008 to October 2017. The results are relevant to river and estuary entrances with moderate to strong river flows and/or tidal prism. [ABSTRACT FROM AUTHOR]

Black, K.P.; Reddy, K.S.K.; Kulkarni, K.B.; Naik, G.B.; Shreekantha, P., and Mathew, J., 2020. Salient evolution and coastal protection effectiveness of two large artificial reefs. Journal of Coastal Research, 36(4), 709–719. Coconut Creek (Florida), ISSN 0749-0208. Two offshore reefs constructed at Ullal, Karnataka, on India's west coast, are exhibiting coastal protection benefits. The reefs are large (275 m and 325 m long) and uniquely placed well offshore (600 m and 760 m) in intermediate depths (6 and 7 m below chart datum). Their crests are between low-tide and midtide level. Bathymetric and beach surveys show that sand has accumulated to form two evolving shoreline salients, which are currently 2–3 times the length of the reefs. The salients have grown underwater on the inner shelf to create a large sand-retention zone up to 1 m thick and stretching from the beach to the distant lee of the reefs. The reefs are the first protection structures that have restored the beaches and enhanced sand storage over this broad, severely eroded region, both inshore and on the inner shelf. Prior rubble-mound rock revetments (seawalls) and 50–70-m-long groynes failed to restore the beach in stormy monsoon conditions, while the inner shelf continued to erode. The reefs were designed using a combination of computer simulations, measurements of natural salients in India, and empirical relationships. The methodology that led to the reef shapes/sizes and their position offshore is discussed, along with monitoring results. [ABSTRACT FROM AUTHOR]