Grewingk Creek drains a glaciated watershed of 29,138 acres (11,792 ha) and flows northwest for 3.5 miles (5.6 km) from the terminus lake of the retreating Grewingk Glacier to the south-eastern shore of Kachemak Bay, about 24 miles (39 km) north-east of Seldovia and 13 miles (21 km) east of Homer, Alaska. Grewingk Glacier extends northwest for about 12 miles (19 km) from an icefield to its terminus lake on the southern Kenai Peninsula. The glacier and creek were named in 1880 by William H. Dall of the US Coast and Geodetic Survey, after Constantin Grewingk, who in 1850 published papers in German on the geology and volcanism of Alaska.

Retreating glaciers generally produce high river discharges, large volumes of sediment and steep channel slopes. River channels emanating from these glaciers respond to such discharge by developing a braided pattern with multiple channels separated by bars or islands. A braided river flows, over some part of its length, in multiple mobile channels across a gravel floodplain. Braided channel systems are high-energy and variable, so channel configurations constantly change. Three factors are probably necessary for braiding to occur: an abundant sediment supply; erodible banks; and high-energy stream velocity.

When glacial rivers reach the sea, the resulting beach sediments can be highly dynamic, with erosion events caused by storm-driven waves and deposition events caused by glacier surges and retreats. In Kachemak Bay, during periods of relative sediment stability, animals such as barnacles and mussels, and algae such as rockweed and sea lettuce, colonise the beach face, creating multi-colored patterns. Since the slope angle is low, the intertidal zonation stretches into wide bands, with each representing the algae and invertebrates that can tolerate different levels of exposure to air and sun during the twice-daily tidal fluctuations. Read more here and here. Explore more of Grewingk Creek and Kachemak Bay here: