Update on the California Levee Database 

TO #2 Risk Factors Data Collection Task 

The following is an update on California levee database effort and Task Order 2 - levee 
database and the risk factor data collection and prototype application. 

The levee alignment and attribution collection aspect task within Task Order 2 is 
complete. PBS&J has collected levees for the entire state including all 58 counties. This 
effort involved review of approximately 2,770 USGS quads, rectified and reviewed 860 
FEMA FIRMs and used Digital Ortho Quads coverage (DOQs - aerial imagery) to check 
data spatial alignments. Existing digital levee data was merged with the data capture form 
the USGS quads and FEMA FIRMs and check for location accuracy against the statewide 
DOQs. The scale of the data collection was done at approximately USGS quad scale 
(1:24,000) for most of the data. The DOQs are somewhat better then 1:24,000 so the 
accuracy of the data is some where between +/- 33.3 to 40 feet per national map accuracy 
standards. Over 147 communities were contacted for collection of data. The levee 
geodatabase consists of approximate 13,740 miles of spatially located levees, canals, and 
flood control features totaling 8,712 records. A geodatabase feature class has been 
developed to house the levee information. The feature class is populated with the 
preliminary set of attributes that include: 

Unique ID assignment 
Primary Use 
Structure Type 
Maintenance Agency 
Owner Agency 
Local Authority 
Construction Agency 
Year Constructed 
Flooding Source (i.e. Stream name) 
Location Description 
Data Source 
Bankside (i.e. Left/Right) 
Category (i.e. Project/Non-Project) 

Additional attribute information is associated through relationships to other feature 
classes including: 

County Name 
Assembly District 
Congressional District 
Senate District 
Reclamation District 
24k Quad 
100k Quad 
250k Quad 


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Hydrologic Unit Name 
FEMA Flood Panel 

The database Entity Relationship Diagram (ERD) illustrates these relationships and is 
attached as an appendix. The ERD attached is the latest version of the database, as DWR 
moves forward with work on the database additional table and feature classes will be 
added to the database. Currently the database is expanding to include geotechnical and 
integrity information such as borehole locations, erosion sites, and high water marks, 
relief wells, sand boils, encroachment points, levee crossing points, piezometers, and 
failure points. 

The information collected from the various sources required a large amount of 
verification and clean-up. Below is an example of the type of work performed on the data 
to update and validate the data. 

Example of rectified data using Digital Ortho Quads (DOQ) 



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Emphasis was placed on locating 
levees spatially by reviewing 
USGS quads and georeferenced 
FEMA FIRMs. The data was then 
spatially verified/rectified using 
aerial imagery which consisted of 
state DOQs. The attribution level 
of the records varies by attribution 
fields within the database. We 
have attributed 100% or close to 
100% of the following fields in the 
database: assembly, 
congressional, and senate districts, 
county name, hydrologic units, 
24k, 100k and 250k Quads, left 
and right bank, stream name, and 
project/non project levees. 83% of 
the levee miles have structure type 
along with 51% miles for the 
primary use attribute. Roughly 
25% of the miles have owner and 
maintenance entity populated. 

Extent of levee information 


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Delta Region 

Stream stationing for the major streams within the central valley was captured off of the 
USGS Quad map as part of the data collection effort. The stream station is a separate 
layer within the GIS. Additionally, stationing for levees within the delta region was 
obtained from the DWR - Delta group. Additionally, existing levee stationing 
information for various areas has been scan and rectified and can be used in the GIS as 
reference data for the levee database as shown on the following page. 


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Stream Stationing 


Levee Stationing Reference Information 

PBS&J has been actively coordinating the DWR effort with USACE and FEMA as part 
of this task order as well as thru other means. PBS&J has given several presentations on 
the DWR levee database and has also attended several workshops on the USACE 
national levee database. PBS&J continues to receive the latest version of the USACE 
database from the Sacramento District. 


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The database is being delivered in a geodatabase format for use with ESRI ArcMap 
software and an Oracle database as requested for David Parker. We are currently working 
with David to make sure the structure will meet DWRs future needs. 

PBS&J has completed the work on the Task Order 2 -Risk Factors data indexing. 
PBS&J has reviewed a portion of the levee and floodplain documents at Santa Clara 
Valley Water District (SCVWD) as part of the risk factors development subtask within 
Task Order 2. This task is to begin the development of a library of existing information 
and documents associated with the levee systems in California. SCVWD was selected as 
part of this to prototype the database and system to retrieve the information data. The task 
look at several ways to link the library information to levee reaches and we settled on 
linking the library data to the unique levee ID by reviewing the documents and then 
assessing what levee reaches were associated with the that particular document. A MS 
Excel spreadsheet was used to initially capture the document attributes and the levee ID 
were captured directly from the levee geodatabase. 

Several site visits were made to SCVWDs record libraries to review and inventory the 
appropriate documents. Data collection was focused on as-builts, planning studies and 
maintenance logs to provide sufficient sampling of risk factor data for purposes of 
preparing the pilot risk factor analysis application. The as-built review completed under 
this task order represents approximately 60% of available data, planning document 
review an estimated 40%, and maintenance log review 100%. The maintenance log 
review completion percentage considers only the most recent maintenance assessment. 
The information collected as part of the risk factors subtask has been compiled into a 
database table to link to the main levee database. 

The onsite data collection effort was divided into two visits to provide sufficient time to 
evaluate the methodology and review the results and allow for any refinement or 
resolution to challenges faced. The evaluation and review is documented below. 

Summary 

 There are 161 reports classified as floodplain management documents within the 
Santa Clara Valley Water District (SCVWD) library that have been reviewed to 
date. The initial step in the review process requires examination of the document to 
determine if levee data is contained within the report. At this time, 55% of these 
documents contain levee data. The remainder of the documents contains 
information relevant to stream segments but not levees. The stream name was 
captured for these documents and the associated stream segment captured in a 
tabular format. 
 Roughly 5% of the documents referred to levees that have not been captured within 
the levee database. These levees were realized as a result of additional research and 
when identified in planning documents the levees were verified in an operations and 
maintenance manual, inspection log, or other post-construction documents as having 

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been built. In this instance, the document and the type of information contained 

were cited and the levees will be added to the database later 

 Another 5% of the documents require additional post-processing to be performed 
following the initial research period. The levee ids were not extracted immediately 
from the document due to the large number of associated levees and these 
documents also contained a project area map that allows for efficient postprocessing. 
 Review of data proved to be a significant effort because the studies covered a 
variety of locations making it difficult to be very inefficient at the document review 
and analysis having to locate each individual levee. The review of planning 
documents can not be organized by the geographical locations, whereas the review 
of the as-built drawings may be better defined by project area. We are supplying the 
SCVWD with the locations of the drawings we intend to review and the water 
district is gathering the applicable drawing sets. 
 Maintenance logs were also reviewed. The most recent maintenance log data is 
included as a single row entry for each stream maintained. Maintenance logs are 
link to many levee segments since the logs cover a large area and are not broken out 
by levee reach. 
 Hydraulic models are available on the SCVWDs website and these are also being 
used in post processing to supplement the ability to capture levee identification 
numbers during post processing 
Challenges Encountered and Resolutions 

Challenge 1: Documents not able to be associated with levee identification numbers 

Description: This poses a problem with the current levee database as the primary key to 
the database is the levee ID. The current application architecture does not readily fit this 
scenario. The application can eventually accommodate these documents through 
alternative search methods. However, these alternatives will need additional research and 
evaluation prior to implementation. It is possible that the stream name could be used as 
secondary search key. Using the stream name though, poses additional challenges as 
naming of streams can change along their course and can also be referenced by different 
names in different source documents potentially cause confusion. Additionally a stream 
layer has not been fully developed that can be used uniquely identify each stream reach. 

Resolution: These documents will continue to be cataloged but will not be searchable 
in the prototype application to be delivered in this task. The recording of the appropriate 
information in the database is a small part of the entire effort. SCVWD and DWR may 
also find the cataloging of the documents useful in the future. Means of incorporating 


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such documents into the search capabilities of the application will continue to be 
evaluated and proposed methodology will be delivered at the conclusion of this task 

Challenge 2: During document review new levee features have been identified 

Description: These levees were realized as a result of additional research and when 
identified in planning documents the levees were verified in an operations and 
maintenance manual, inspection log, or other post-construction documents as having been 
built. In this instance, the documents and the type of information contained were cited, 
but the levee not added to the database. 

Resolution: Any new levees discovered during the document review will be 
documented and held for incorporation into the levee database in a future data collection 
tasks. 

Challenge 3: Additional post-processing requirements were noted for capturing levee 
identification numbers. 

Description: Some documents reviewed encompassed numerous levee features and it 
was not efficient during the document review to identify each individual levee 
identification number. It was determined that post-processing through other means (e.g. 
spatial overlay) might provide a more efficient method of capturing these attributes. 

Resolution: Some post-processing time had been accounted for in the budget for this 
effort and it has been determine at this time that the budget reserves for this type of post 
processing is sufficient for the required effort. 

The risk factors that are being used to index the data and consist of 8 main categories 
with sub categories as listed below: 

. Topography 
. Surveys 
. Conventional 
. IFSAR/LIDAR/etc 
. Hydrologic data 
. Documentation/HEC Models 
. Documentation/Other Models 
. Hydraulic data 
. Documentation/HEC Models 
. Documentation/Other Models 
. Geotechnical 
. Stability 
. Seepage 
. Erosion 

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. Materials/Soils 
. Borings/Lab/Reports 
. Settlement/Subsidence 
. Historical information 
. Certification 
. Aerial Photos/Maps 
. High Water Marks 
. Breach/Boils 
. Operations information 
. Closure Gates 
. Evacuation Plans 
. Flood Fight Support 
. Construction information 
. Design Documents 
. Construction Drawings 
. Levee Materials 
. Inspection/Maintenance information 
. Vegetation 
. Structures Thru/Encroached 
. Erosion/Deposition Control 
. Armament 
. Rodents 
Additional sub-categories can be added as needed. The document metadata has been 
compiled into a database, linked to levee segments, and indexed by risk factors. A 
prototype internet mapping application to view and search the data has been developed 
that allows the user to search both by a tabular method and geographically within a 
mapping GUI. The search can be based on many of the captured attributes about the 
document. As seen below the user can search on name or a portion there of, document 
type, source, date, location, risk factors, county, stream, or levee ID. 

The application and database clearly allow for the inventory and assessment of exiting 
hard copy information at the County to be link to levee reaches as historical information 
on the levee systems in Santa Clara. The format used to record the documents allows for 
a multiple variable search of index documents to recall Linking existing library 
documents is one way of building a data store of pertinent information on the current 
levee systems. As evaluation of the levee systems in California continue, the data capture 
as part of Task 2 will allow for quick recovery of existing archived data. 


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Data Collection Spreadsheet 


Web Application Document Search 


Search Results 


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The following results page depicts the document information collected on each of the 
documents including the risk factors and associated levees. 



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Document Details Result Page 

The Geospatial search is an ESRI ArcIMS based GUI that allows the user to search for 
documents based on levee ID, stream name, stream name and stream station as well as 

county. 
Web Mapping Geospatial Search Screen 


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Geospatial Search Results Tab and Document Details 

The pilot application has been complete and presented to DWR. Minor revisions will be 
made based on the presentation by PBS&J to complete the project. A user guide has been 
developed for the application as reference. The application will be hosted by PBS&J until 
DWR has the ability to host the application. 


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APPENDIX A 
LEVEE DATABASE 
ENITY RELATIONSHIP DIAGRAM