2. Introduction

8. Model Description 

2.1   Why was this Model Created?    2.2  For Whom is this Model Intended?    2.3  What Can CRYSTAL do?    

2.4  What Software was Used?    2.5  General Overview

2.  Introduction 

The Cascade Regional Yield SimulaTion and AnaLysis Model (CRYSTAL) is a highly interactive modeling tool, allowing water managers, planners, and public officials in the Tri-County (Pierce, King, Snohomish counties) area to create a shared understanding of how the region's water supply systems operate and are managed. Additionally, the CRYSTAL model facilitates the exploration of the impacts of various future regionalization, expansion, and conservation alternatives that will allow the system to meet the regional water supply and natural resource needs in the future.

CRYSTAL was created as an element of the University-wide Puget Sound Regional integrated Synthesis Model (PRISM) project. Dr. Richard Palmer, Amy Groome, and Sherrill Nelligan-Doran of the Department of Civil and Environmental Engineering of the University of Washington constructed the model in 1999. The CRYSTAL model extends previous research performed by Dr. Palmer and former graduate students including Larry Karpack, Selene Fisher, Allison (Keyes) McKeven, Jay Lund, Eric Hagen, and Andy Wood. This model was built with input from central parties in regional water supply planning: Tacoma Water, Seattle Public Utilities, City of Everett Public Works, Snohomish County Public Utility District No. 1 (SnoPUD), CH2M HILL, US Army Corps of Engineers (USACE), and the Muckleshoot Indian Tribe (MIT). CRYSTAL was created in the Powersimâ Constructor 2.51 simulation environment and in Microsoft EXCEL Office '97(EXCEL).

The Puget Sound area is noted for its rich water resources. However, recent droughts have demonstrated that existing municipal water supplies will not be able to meet increasing demands during the next 40 years. CRYSTAL evaluates current water resources facilities and explores future supply and conservation alternatives and their abilities to meet growing water demands. The model integrates individual utility water demands, conservation programs, and supply options into a single analysis tool. CRYSTAL represents the most comprehensive regional water supply planning model yet developed for Puget Sound.

CRYSTAL was constructed with input from the major water utilities and other public resource agencies. Following numerous individual agency meetings, a workshop was held in May 1999 to assemble these groups and evaluate the underlying modeling assumptions within a Shared Vision approach (Palmer, 1999; Keyes and Palmer, 1995; Palmer et al., 1993)