2024-11-1 Chuck Flaherty Testimony GP 2045 1 of 2

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PROJECT DOCUMENT Date: April 18, 2016 Authors: Amy DeBay, Ian Varley, Doug Walker Introduction Task S2 (Land Use Allocation) setsup a framework for estimating future development patterns (amounts and location) based on a set of rules. Task E (Trend Scenario) uses an initial, calibrated run of the allocation model to estimate future development patterns based on historical trends. These tasks go hand-in-hand and are combined in this technical report. Allocation Concepts and Approach Future development patterns (amounts and location) are estimated using an algorithm-driven process called allocation. Allocation models the interplay between market demand for development in certain locations (“desirability”) and amount of development allowed according to current regulations or by future land use patterns suggested by alternate scenarios (“capacity”). Given a pre-determined amount of growth expected in the given time frame (here, new growth between 2015 and 2040), the allocation process estimates where each incremental unit of new development will go, following the basic presumption that the most desirable areas will be developed first, capacity allowing. Thus highly desirable areas are assigned growth first, and then slightly less desirable areas get developed next, etc., until all the estimated growth amount has been accommodated. Numerous refinements to the basic principle are used to produce the final estimates. For example, parcels aren’t always filled all the way to capacity, a certain amount of controlled “randomness” is often applied to the growth pattern, etc. For mixed use areas, both residential and non-residential growth can be assigned. In this study, a CommunityViz tool called Allocator 5 is used. The methods combined with the algorithms in Allocator 5 provide a well-reasoned analysis that will be helpful for this and myriad other planning studies, but it is recognized that the results have limitations in terms of modelling precision and confidence. The CommunityViz allocation method is sometimes described as “light-weight” to “medium-weight,” differentiating it from the “heavy-weight” algorithms such as UrbanSim or PECAS that are considerably more sophisticated but are more difficult and expensive to implement. In contrast, the Allocator 5 method is easier to use and lends itself well to “what-if” type scenario planning. At the highest level, the allocation algorithm takes 3 inputs—growth amount, capacity, and desirability—and generates 1 output—a pattern of future development. Our methods for each of these are described next. Growth Amount As a 2015 baseline for housing unit data, Placeways used data from the County’s Real Property Tax (RPT) office to identify the number of housing units and non-residential square feet. The procedure began with a database file from RPT that, unfortunately, lacked metadata, so the fields were interpreted manually. For each TMK, buildings were converted to housing units where appropriate Trend Scenario and Land Use Allocation Technical Report 1