Element 4 - Geographic Information Systems

What Can We Do With Geographic Information Systems?
The Water Protection Program, or WPP, has a fairly extensive Geographic Information System (GIS) tool. GIS allows for visualization and analysis, and helps simplify data management.

Digital mapping tools allow better management of Missouri's Water Quality Standards (WQS) and provide more transparency during the rulemaking process. The department uses interactive map viewers as its online GIS interface, which allows the public to view and query data in a map setting. For more information on available data, visit the following link: http://www.msdis.missouri.edu/data/newdata.html .

Visualizing With GIS
The WPP uses GIS to create feature classes for much of what is maintained and regulated. The first feature class created was the EPA approved 303(d) Impaired Waters List. It now includes the 305(b) Water Quality Assessment (WQA) List, waters listed in effective WQS, permits, etc. Being able to visualize these components is invaluable to the department. It easily shows physical locations in the state and helps maintain continuity in regulations.

Analyzing With GIS
The real power of GIS lies in its ability to allow for the analysis of information. This can be accomplished through manual visualization or automated processes such as flow traces, watershed delineations, etc. For the WPP this assists the various sections to visualize and work with data created by others. For example, permit writers look at a facility location on a permit application and determine what watershed the permit will be in, locate the first receiving water body and first classified water body and then determine if there are any impaired water bodies that may be affected by the feature for which the permit is being requested.

Simplify Data Management
The management of all data maintained within the WPP is simplified by using GIS. This is achieved first by merging the GIS data with the data stored inside the Missouri Clean Water Information System (MoCWIS). See more about MoCWIS later in Element 4. By using automated processes to merge the data together focus is maintained on making sure data is in the right place. This greatly reduces the risk of information being put in the system incorrectly. The resulting benefit is better data quality.

How Often Is The Data Updated?
There are two main types of data to consider when discussing data updates; spatial and attribute. Much of the attribute data is stored in the various components of MoCWIS (WQS, WQA and permitting, to name a few). Attributes for each of these are updated at varying intervals, ranging from every night for components such as permits, to every couple of years as needed to meet EPA requirements, or as part of a rulemaking. Spatial updates and periodic synchronization with the national NHD are an ongoing process, as time and resources permit.

What Is Spatial Accuracy?
The data used in the WPP has evolved greatly since the beginning when the 1:100K National Hydrography Dataset (NHD) was used to build some of the early feature classes (more on NHD later in this Element). This data is known as medium resolution data, a good stepping stone to where the department’s data management is today. Now the 1:24K NHD is used, also called high resolution data. This data was originally built from the United States Geological Survey (USGS) topographic maps. All of the WPP data uses the 1:24K NHD as its foundation The importance of this is evident in the fact that the department is the NHD data steward for the USGS, meaning the responsibility for making many of the edits to the location of water bodies in the state is the department’s responsibility. When it comes time to edit the data, the department uses leaf off aerial imagery that was acquired in 2008. There can be some discrepancies from the real world due to the changing nature of water bodies as a result of floods, droughts and other conditions. For a known accuracy the department’s data is plus/minus 40 feet.

What Is The Attribute Accuracy?
Over the course of time the attribute accuracy of the data used by the WPP has been edited to eliminate many of the redundant data entries. Links have been created between GIS, and MoCWIS, and processes run overnight to move information around as appropriate. This improves staff time as data is only entered once, which can also reduce the likelihood of errors. Subject matter experts are the primary individuals entering data, which adds a safeguard so errors are caught that others not as familiar with the data might miss.

How Much Data Are We Maintaining?
The WPP maintains a significant volume of data, with data maintenance needs being driven by the type of data and the functions they serve. WQS currently has 13 feature classes being maintained, permitting and compliance have 3, WQA has 13, and TMDL has 3. Examples of some of these feature classes are:

  • Use Attainability Rating
  • Stream Survey Monitoring Locations
  • Nonpoint Source Areas
  • Toxic Event Streams/Lakes
  • Water Quality Sample Locations
  • Impaired 303(d) Stream/Lakes
  • Dam Points
  • Watersheds
  • Waste Water
  • CAFO
  • Stormwater

 It takes considerable resources to perform the spatial and attribute updates and would be very difficult to maintain if it wasn’t for the integration of the various systems. Great strides have been made since 1998 when the first GIS feature class was built. Currently the department is using GIS to show proposed rule changes to WQS. This will allow interested parties the ability to actually visualize what is being proposed by the rule and see how it affects them. Regular updates with the NHD will continue to occur, helping synchronize the data that is dependent on it.