The current level of flood protection varies along the River length as illustrated by the differing return periods. In the upper reaches the point source data indicate flood protection is generally greater than the 50-year level, apart from an isolated region near and downstream of the Aliso Canyon Wash. In the ARBOR Reach, delineated in the figure by polylinear segments, the current flood protection estimates indicate lower levels of protection. However, these interim estimates are in the process of being updated using improved two-dimensional floodplain models by the US Army Corps of Engineers as part of the ‘Los Angeles River ARBOR Reach Floodplain Services Study’. These more accurate results are anticipated to be available in the Fall of 2016 and will be incorporated into future efforts. The lower reaches of the River have flood protection exceeding 100 years, which is a result of the LACDA improvements that were completed in 2001.