Estelle Mountain Reserve. The Lake Mathews area is an important bird resting and feeding site, particularly in the winter months. In addition to a variety of ducks, double-crested cormorants (Phalacrocorax auritus), western grebe (Aechmophorus occidentalis), eared grebe (Podiceps caspicus), golden eagles (Aquila chrysaetos), and bald eagles (Haliaeatus leucocephalus), are present during the winter. Effects on Santa Ana River flow Lake Mathews was constructed in a basin formerly traversed by Cajalco Creek; thus, any water flowing down the creek enters the reservoir. Cajalco Creek is a tributary of the Santa Ana River via Cajalco Canyon Creek into Temescal Creek. The original course of the creek, before 1933, can be seen on the US Dept. of the Interior's 1898 topographic map of the Elsinore Quadrangle. In 2003, the California State Water Resources Control Board found the MWD's interruption of Cajalco Creek water to be in violation of state water code. An out-of-court settlement was reached where MWD would monitor the quantity of water entering Lake Mathews from the creek and release 1.3 times that amount, minus dam seepage, into the Santa Ana River. In addition, MWD was ordered to contribute $50,000 to aid in the removal of non-native arundo grass (Arundo donax) from the Santa Ana River course. Controversy over recreational use Since its dedication in 1940, the reservoir has been fenced off and closed to public access, supposedly to preserve water quality. The MWD has always been concerned about water quality and prohibits body contact sports like swimming in its other nearby reservoirs that are open for recreation, Lake Skinner and Diamond Valley Lake. Mathews is of greatest importance as its outlet feeds directly into pipelines that connect to member water agencies serving 8.4 million people. During its existence, a number of attempts have been made to gain access to the lake for various purposes, but none have been granted. One of the most interesting was a 1952 request for a movie shoot at the lake. The scene from the 1953 movie Fair Wind to Java would have featured, among other things, a smoke-belching volcano constructed on one of the lake's islands. After their idea was rejected by the MWD Board, the movie's producers reportedly constructed a lagoon and volcano on a studio backlot. In 1960, the Riverside County Board of Supervisors mounted an unsuccessful campaign to open the lake for recreational purposes. The board generated a resolution citing a "pressing