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The LA River Master Plan’s existing conditions inventory and analysis revealed that conditions in and along the LA River vary widely, with some areas experiencing unique vulnerabilities and others containing a variety of desirable assets.
To evaluate which portions of the LA River are most in need when it comes to fulfilling the goals of the Master Plan, a GIS-based needs analysis was conducted for each goal.
For each LA River Master Plan goal, criteria for evaluating the magnitude and spatial distribution of need were established using the most applicable datasets collected as part of the existing conditions analysis phase. Individual datasets were rasterized to a common 1-acre grid cell, reclassified on a scale from general need to very high need, and then weighted and combined to produce a relative need assessment for each goal.
Datasets were converted into a need assessment based on either score, density, or proximity that rank conditions across the county. A scale of general need to very high need was assigned based on the relevant goal. For example, for flood risk reduction need, areas not in a floodplain were assigned no need, areas in the 0.2% floodplain were assigned general need, and areas in the 1% floodplain were assigned very high need.
Existing score-based datasets were reclassified to match the same general to very high need scale. For example, CalEnviroScreen scores were reclassified so that areas with better environmental conditions had general need and areas with worse environmental conditions had very high need. For some datasets, a density or proximity analysis was used for assessing need. A density analysis evaluated the number of positive or negative assets in an area relative to LA County as a whole. Proximity was used for datasets where need was relative to an area’s distance from a particular asset.
For more information on the weighting of data in relation to the needs maps, see Appendix Volume II: Technical Backup Document.
Sites and Need
Each site has undergone an assessment to determine the level at which it demonstrates need in relation to each of the nine Master Plan goals. A need score falls within a range of “general” to “very high”. For sites, the need score for each goal is determined by averaging all goal-based need scores within a site boundary. Need is derived from a watershed-wide analysis, thus a site’s need score indicates a future project’s ability to address regional shortfalls for certain Master Plan goals.