Humpy Creek drains a watershed of 6,912 acres (2,797 ha) and flows northwest for about 4.5 miles (7 km) from Emerald Lake in the Kenai Mountains to the southeastern shore of Kachemak Bay, about 67 miles (108 km) southwest of Seward and 14 miles (22.5 km) east-northeast of Homer, Alaska. The creek’s name, first published by the US Geological Survey in 1950, likely refers to the pink, or ‘humpback,’ salmon that spawn here. Emerald Lake lies at an elevation of 1,138 feet (347 m) and is fed by streams draining alpine cirques. The Kenai Mountains, a subrange of the Chugach Mountains, rise to 6,612 feet (2,015 m) and were formed by an accretionary prism composed mainly of metamorphic and igneous rock. This region lies along an active subduction zone marking the boundary between the North American and Pacific plates, which converge at 2–3 inches (6 cm) per year. Subduction shapes the regional bedrock, causes earthquakes, and fuels eruptions of Cook Inlet volcanoes. The Kenai Mountains belong to the Chugach terrane, composed of accreted ocean-floor rocks. The Humpy Creek watershed lies within the McHugh Complex, which consists of deformed sedimentary and volcanic rocks scraped from the sea floor. The primary rock types, from base to top, include basalt, chert, argillite, graywacke, and limestone. The basalt and chert range from the Middle Triassic to the mid-Cretaceous . Graywacke is Early Jurassic in some places, mid-Cretaceous in others. Permian limestone blocks, believed to be seamount remnants, mark a now-subducted segment of Paleozoic ocean floor.

Humpy Creek and nearby streams drain short, steep, recently deglaciated watersheds, resulting in relatively low concentrations of primary nutrients entering Kachemak Bay. Deglaciation of the Cook Inlet Basin began around 15,000 years ago, and the ice that once filled Kachemak Bay had receded by 12,000 years ago on the north shore and by at least 10,000 years ago on the south shore—making the area habitable for early human settlement. Archaeological excavations in Aurora Lagoon, about 3 miles (5 km) north-northeast of Humpy Creek, suggest that the maritime Ocean Bay people occupied the site roughly 4,500 years ago. A more advanced culture is believed to have lived on Chugachik Island, about 7 miles (11 km) to the north-northeast, some 4,000 years ago. The longest-lasting and most widely distributed prehistoric cultural group in the area was the Kachemak tradition, which thrived from about 3,000 to 1,500 years ago. Major excavations on Yukon Island, at Cottonwood Creek, near Halibut Cove, and on Chugachik Island have yielded more than 6,000 artifacts associated with the Kachemak tradition. These include evidence of fishing techniques such as weighted nets for harvesting large quantities of salmon. The Kachemak people abandoned the bay around 1,500 years ago, possibly due to glacial advance or food scarcity resulting from a population increase—estimated at 200–400 people—and the difficulty of storing salmon in bulk. There is some evidence that Dena’ina Athabascans began migrating into Kachemak Bay from the Mulchatna and Stony River areas about 1,000 to 1,500 years ago. Humpy Creek was likely an important area for fishing, food gathering, and hunting.

Humpy Creek lies within Kachemak Bay State Park, Alaska’s first state park, designated in June 1970. The park and adjoining wilderness area now encompass nearly 400,000 acres (161,874 ha). Kachemak Bay is recognized as a critical habitat area due to its biodiversity and biological productivity, which is reportedly three times higher than elsewhere in lower Cook Inlet. Marine mammals in the bay include harbor seals, two species of porpoises, sea otters, sea lions, beluga whales, orcas, and humpback and minke whales. Sea otters have only recently reestablished themselves after being eliminated from the area in the early 1900s. Humpy Creek lies between Grewingk Creek to the south and Portlock River to the north. It is sometimes confused with the larger Grewingk Creek, just 1 mile (1.6 km) to the southwest, which lacks a salmon run. Although Kachemak Bay has no major salmon rivers, 25 streams support anadromous fish runs, some of which are recently enhanced or artificially created. Humpy Creek receives a small run of chum salmon in early August and a substantial run of pink salmon from mid to late August. Between 1960 and 2006, the average annual pink salmon escapement was 47,300. By contrast, 4–10 million salmon typically enter Cook Inlet each year, but relatively few enter Kachemak Bay. The 12.6-mile (20 km) Emerald Lake Loop Trail begins at the mouth of Humpy Creek, tracing the high tide line through grasslands before climbing into forest. The trail offers views of the Humpy Creek watershed and Grewingk Creek’s glacial flats, then intersects the Emerald Lake Trail and ascends to Portlock Plateau for dramatic views of Kachemak Bay. Read more here and here. Explore more of Humpy Creek and Kachemak Bay here: