Evacuation Safety Planners
February 16, 2016
Joan Hickey
City of San Marcos, Texas
Department of Environment & Engineering
630 East Hopkins
San Marcos, Texas 78666
Dear Joan:
This letter and the attached report are to inform you of the current status of the flood analysis research
project for the City of San Marcos, Texas. Immediately following the September 11th acceptance of
ESP’s proposal to study flood analysis for the City of San Marcos, Texas, ESP began implementing the
details described in the project proposal. The progress of the study is going as planned.
Please refer to the following progress report for details concerning work accomplished, work currently in
progress, and work planned for the remainder of the project period. Contact me if you have any
concerns associated with the project.
Best Regards,
Jason Haycock
Evacuation Safety Planners
Project Manager
Project Description:
The study will provide evacuation routes to emergency shelters for residents living in flood risk areas.
This will be accomplished by investigating and analyzing low water crossings, potential flood areas, and
damage assessment information in the San Marcos, Texas Extraterritorial Jurisdiction.
Risk
assessment will also include an evaluation of potentially at-risk households in flood prone areas.
Defining appropriate evacuation networks is the most important objective of the study.
Purpose:
During the past ten years, two floods in San Marcos, Texas have caused water levels to exceed
portions of the Federal Emergency Management Agency (FEMA) 500-year floodplain. Based on data
collected after the 1998 flood in San Marcos, Texas, this study hopes to discover the areas that are
susceptible to damage by flooding and to identify evacuation routes away from these areas and toward
designated emergency shelters. Floodplain management is a community corrective and preventative
program for reducing flood damage. By analyzing annual income levels and other demographic
classifications in the floodplain area, ESP will assess the ability of at risk residents to actually reach
designated shelters. This study will also investigate potential emergency shelters that may exist for
emergency purposes in the future. This information will be based on the master plan developed by the
City of San Marcos, Texas. Many new districts will be rapidly expanding and implementing new roads
and buildings.
These as well as existing transportation networks will provide the framework for
determining appropriate evacuation routes and emergency shelters.
Scope:
This study will cover the San Marcos, Texas Extraterritorial Jurisdiction up to and including the
proposed expansion of the city in the master plan. Development of evacuation networks will rely on
current and future infrastructure and account for temporal changes in population and geographical
growth of the City of San Marcos, Texas.
Progress:
The progress of the project is going as planned. The final deliverables will be presented as scheduled
on December 8th, 2006. The timetable below illustrates the schedule framework for the project. At this
point ESP is completing the data processing phase and working through data analysis and
interpretation.
Week
Dates
Data Collection
Data
Processing
Data Analysis
Interpretation
Deliverables
and
Review
1
Sept.
25th
2
Oct.
2nd
3
Oct.
9th
4
Oct.
16th
5
Oct.
23rd
6
Oct.
30th
7
Nov.
6th
8
Nov.
13th
9
Nov.
20th
10
Nov.
27th
Work Completed:
Data collection and processing were the focus of the initial project timeline. ESP has managed and
prepared data that will be incorporated into the analysis and interpretation phases of this study.

Overlay analysis of FEMA 100 year and 500 year floodplains and the flood line of 1998 were used
to determine at-risk areas within the Extraterritorial Jurisdiction of the City of San Marcos, Texas.

Low water crossings have been identified using overlay analysis. Low water crossings were
determined by identifying portions of the San Marcos road network that crossed potential flood
areas. Potential flood areas were designated by FEMA floodplain data and the 1998 flood line
data acquired through the City of San Marcos, Texas.

Emergency shelters have been determined by evaluating size and location.
Shelter
determinations required that structures be outside the established FEMA floodplains as well as the
1998 flood line.
Development of future infrastructure will be important for forecasting future
emergency shelters.

Risk assessment of land parcels based on the 1998 flood damage report has been assigned. The
tabular data acquired from the City of San Marcos was joined to parcel tabular data of the San
Marcos Extraterritorial Jurisdiction.
Work In Progress:
Data analysis and interpretation are the main focus of the work currently in progress.
Data
management is an on-going aspect of the project and will continue throughout the course of the
scheduled timeframe.

Risk assessment based on demographic data is currently underway.
This analysis will be
incorporated into the study in the same fashion as the 1998 flood damage report.

Formation of the associated metadata has begun and will continue throughout the course of the
study. All data used within the GIS will be assigned metadata based on federal standards using
the ArcGIS Metadata Wizard.

Development of ESP’s website is underway and will continue throughout the remainder of the
study. The website will be a collaborative effort between ESP and FADDEN consultants. The
continuing progress of the project can be monitored by accessing the website.
Work Planned:
The study will progress with the development of evacuation networks. This portion of the study will be
the primary focus of the data analysis phase. Also, development of the final deliverables and reviewing
the results of ESP’s findings will be the focus of the final portion of this study.

Network analysis will be used to establish evacuation routes within the Extraterritorial Jurisdiction of
the City of San Marcos, Texas. This analysis will be the major focus of this study and will
incorporate all other aspects of the analysis model developed by ESP in the project proposal. This
analysis will be accomplished by using the Network Analyst extension of the Arc GIS software.

The final deliverables will include easy-to-read flood emergency evacuation maps based on the
network analysis. These maps will be large-scale documents to be used by rescue teams in the
event of a flood emergency.

Future growth in infrastructure and population will require forecast maps based on the master plan
developed by the City of San Marcos, Texas.
Temporal consideration will be given for
transportation network detours and infrastructure construction.
Overall Appraisal:
The flood analysis study developed by ESP is going well and on time for the December 8th, 2006
completion date. Continuing progress of the study can be monitored by visiting our website and
accessing the flood analysis project link. Digital copies of the final deliverables may be accessed at the
website upon completion of the project.
In regard to the overall progress of the study, the only problem that has arisen concerns the risk
assessment of households in the City of San Marcos, Texas. Initially, the study aimed at assigning tax
appraisal information to each individual land parcel in the Extraterritorial Jurisdiction of the city. This
goal was not realized due to lack of specific, current, or precise data. The determination has been
made to use census blocks to estimate tax appraisal information and determine at-risk census blocks
as opposed to at-risk parcels. Discussion of this issue will be required to ensure the quality of the
research and the accuracy of this study as outlined in the project proposal.
The final report will outline all aspects of the study and identify details concerning data processing,
analysis, and interpretation. This report will be included as a detailed outline of the project and included
in the final deliverables.