Ballona Wetlands Research Articles

SPATIAL ESTIMATES OF STORMWATER POLLUTANT LOADING USING BAYESIAN NETWORKS AND GEOGRAPHIC INFORMATION SYSTEMS

Stormwater runoff has become the primary source of many pollutants to the Santa Monica Bay watershed (California), and managing stormwater inputs to the bay has become the primary objective of new regulatory efforts. Empirical methods to estimate stormwater pollution have been developed using land-use data; however, land-use data collected from traditional ground surveys are expensive and time consuming and may not be available. This study used an alternative approach and estimated land use from satellite-image classification using Bayesian networks. The results were converted to thematic maps using a geographic information system to visualize spatial estimates of runoff coefficients of the given area, event-mean concentrations (EMCs) of target pollutants, and their pollutant loads. The stormwater-pollutant-loading maps identified areas of high annual-mass loads, which were more affected by impervious areas, because of their high runoff coefficients, rather than their EMCs. In this watershed, the major sources of nonpoint-source pollution are the multiple-family-residential (14%), commercial (7%), public (6%), industrial (3%), and transportation (7%) land uses adjacent to Marina del Rey and the Ballona wetlands. The contributions of single-family-residential (30%) and open (33%) land uses are less important.

The Love of Nature and the End of the World: The Unspoken Dimensions of Environmental Concern

Every day on my way to work, I am confronted by the sight of an enormous construction project—the Playa Vista development—rising before my eyes. It sits about two miles from the Pacific Ocean atop what was once a beautiful and wild place, the Ballona Wetlands. There is a chronic need for housing in southern California and this development aims to address at least some of that need. At what cost, however? The intricate web of wetlands that used to run up and down the California coast has all but disappeared. The egrets and herons and terns and kites and other birds that thrived in the brackish waters of the Ballona Wetlands retain a precarious foothold in the tiny portion of the wetlands that remains. But their habitat has been reduced to a poor and thin remnant of what it once was. Their future in this place is uncertain.

Trace Metals in Fish and Invertebrates of Three California Coastal Wetlands

Metal concentrations were measured in selected fish and invertebrate species from Mugu Lagoon, Malibu Lagoon and Ballona Wetlands in southern California in order to assess the extent of metal contamination in these three wetlands. Ranges of element concentrations (in μg/g) found in biota were: Zn 12–650; Cu 1.9–440; Ni<1–37; Cr<1–55; Pb<0.5–6.8; As<1–8.5; Se<1–3.8; Cd<0.2–0.90; and Ag<0.3–5.9. Relative to previous studies of California biota, the highest metal concentrations found were for chromium and nickel. The highest levels were in one of the two bottom-dwelling fish (juvenile Leptocottus armatus) (55 μg/g) and the two water-column fish sampled ( Fundulus parvipinnis and Atherinops affinis) (30 and 24 μg/g). At Ballona Lagoon, elevated levels of copper and silver were found in the bivalve Tagelus californianus (440 and 5.9 μg/g). Chromium and nickel appeared to be most persistent in fish from Mugu (4.6–55 and 2.6–37 μg/g), the most northern site and an active military base, and Ballona (<1–30 and <1–16 μg/g), believed to be the most metal-contaminated site. Compared to previously measured metal concentrations in species of California coastal waters, these regions revealed higher levels of chromium, nickel, silver, arsenic, zinc, copper and, to a lesser extent, cadmium and selenium. Chromium and silver were present at high enough levels at all three sites to be considered environmental health hazards.