Embalse Arroyito is a reservoir on the río Limay in the Comahue region, straddling the border of Neuquén and Río Negro provinces in northwestern Patagonia, Argentina. It sits at an elevation of approximately 315–316 meters above sea level, roughly 45 kilometers from the city of Neuquén, near the small town of Arroyito. The reservoir covers 38.6 square kilometers with a length of 3,500 meters, a total storage capacity of around 300–361 cubic hectometers, and an average depth of 7.7 meters, reaching a maximum of 15 meters. It is the fifth and lowest of five dams on the río Limay, functioning primarily as a flow regulator for the upstream El Chocón reservoir and as a hydroelectric facility with an installed capacity of roughly 120–128 MW.

The dam itself is a homogeneous loose-material structure 26 meters high and 3,500 meters long, with a concrete hydroelectric plant integrated into its body. The spillway capacity is substantial, rated at over 2,500–3,750 cubic meters per second, reflecting the reservoir's role in managing potentially large flood events on the Limay.

The surroundings attract visitors for day outings, with a campsite situated on the banks of a creek shaded by willows and poplars. The area supports birdlife including black-necked swans and avutardas, making it of interest to wildlife observers. The landscape combines the engineering scale of the dam with the open Patagonian scenery typical of the Limay valley.

Fishing is regulated under the Patagonian continental sport fishing rules, which apply to both Neuquén and Río Negro. The current season runs from November 1, 2025, through October 31, 2026, with a daily limit of one rainbow trout, two perch (perca), and ten pejerrey. From May 2, 2026, all salmonids must be released, and barbless hooks are required. Pejerrey fishing is authorized through August 15, 2026, with approved equipment only. Paddlers should be aware that this is an active hydroelectric facility with regulated water releases, and the dam infrastructure and spillway operations represent significant safety considerations on the water.