Hydro Community
by Paul Robinson, Water Resources Team Leader
Imagine being able to have an idea of where flooding issues are at the outset of a project. What if we could squeeze government dollars a bit harder and quickly map flood risk for a whole nation?
Making good use of available GIS data and new tools in the armory of our profession are rapid flood inundation models like Halcrow’s ISIS-FAST. The tool provides a quick assessment of flooding using simplified hydraulic principles to provide results up to 1000 times quicker when compared to other tools and methods available for flood inundation simulations – i.e. providing results in minutes as opposed to hours or days.
ISIS-FAST works by first identifying depressions on the floodplain before routing water through these depressions. Water depths in the depressions are determined by: volume of water flowing into that depression; level at which water can spill into neighboring depressions; and water level in neighboring depressions. ISIS FAST represents connectivity and volume filling effects on the floodplain, without having to represent detailed hydraulics.
Liying Wang (Florida State University, lwang3@fsu.edu)
Ming Ye (Florida State University, mye@fsu.edu)
Paul Z. Lee (Florida Department of Environmental Protection, paul.lee@dep.state.fl.us)
Richard W. Hicks (Florida Department of Environmental Protection, Richard.w.hicks@dep.state.fl.us)
What does it do?
Nitrate, as a commonly identified groundwater and surface-water pollutant, is associated with a number of adverse health and environmental impacts. One major source of nitrate in the environment is due to wastewater treatment using Onsite Sewage Treatment and Disposal Systems (OSTDS) (a.k.a., septic systems), whose effluent is directly discharged into soils and subsequently groundwater. Therefore, it is important to simulate nitrogen transformation and transport in the vadose zone and groundwater due to septic systems. We have developed an ArcGIS-based Nitrate Load Estimation Toolkit (ArcNLET) to simulate nitrate fate and transport in groundwater and to estimate nitrate load from septic systems to surface water bodies such as lakes and rivers (read the ArcNLET blog). In this blog, we introduce VZMOD, Vadose Zone MODel, a recently developed software for simulating nitrogen transformation and transport in the vadose zone. VZMOD can be used as a pre-processor of ArcNLET to provide source plane concentrations of individual septic systems from the vadose zone to groundwater.
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This month we released the Flood Planning Map, the first in a series of maps and apps to help emergency managers and community leaders prepare for flooding events.
The Flood Planning Map provides flood planners with a set of tools and workflows to prepare for seasonal river flooding. These tools and workflows are based on real-world examples that have been used during previous flood events in the upper Midwest. Seasonal river flood planning is typically conducted weeks or months in advance of predicted crest in each community. This advance notice gives community leaders time to plan for securing assets, protecting infrastructure, or evacuating citizens within the impact area.
The first version of the Flood Planning Map provides the ability to do the following:
- Determine the flood impact area based on predicted flood levels.
- Identify critical infrastructure, facilities, and citizens that could be impacted.
- Create budgetary cost estimates for temporary levees.
- Share the results with others who will execute the flood plan.
The anisotropic nature of meandering river morphology poses unique challenges in analyzing and modeling river channel data using GIS. Standard GIS tools that use Cartesian (x,y) coordinates are not appropriate for dealing with river channels because of their inability to handle river anisotropy – the unequal physical properties along different axes. However, researchers at Purdue University have created custom tools to handle river channel related data in ArcGIS. Those tools compute river attributes, perform spatial analysis and communicate with external hydraulic models. A few examples of the capabilities of Purdue’s river channel tools are given below.
Interpolating Cross-sections to Create a 3D Mesh
The figure below shows how cross-section (black) lines are interpolated to create a 3D (blue) mesh, and then this mesh is converted to a surface through interpolation.
Prepared by: Fernando Salas, Graduate Research Assistant, University of Texas at Austin
Special thanks to Dr. David Maidment (CRWR), Dr. Stefan Fuest and Matt Ables (KISTERS), and Dan Siegel (Esri) for their individual contributions to the design and implementation of the Central Texas HUB.
The central Texas corridor, better known as “Flash Flood Alley,” is one of the most flood prone regions in the United States. In fact, Texas regularly leads the nation in flood fatalities and flood related property damage each year. During a flash flood, rapidly changing water levels can trap both emergency responders and citizens with little to no warning. In order to mitigate risk to residents and infrastructure, citizens and emergency responders need to exhibit “real-time” situational awareness to respond proactively instead of reactively. With the emergence of the internet, mobile communication networks and social media, it is now possible to quickly disseminate information to a vast audience in “real-time.” Furthermore, the emergence of GIS technology and web services has facilitated the creation of easily understandable map applications that readily convert data into actionable intelligence.
Flooding in Central Texas
The USGS periodically reviews the NHD Data model to determine if changes are needed to better suit our community’s needs. These changes must be approved by a panel in order to ensure the NHD community will not be negatively impacted.
The updates to the NHD model are as follows:
1. Removed attribute ComID from all NHD feature classes and tables
- Removed FeatureComID from NHD event feature classes
- Remove d attribute AboveComID and BelowComID from NHDVerticalRelationships table
- Remove d attribute FromComID and ToComID from NHDFlow table
- Remove d attribute WBAreaComID from NHDFlowline feature class
The American Water Resource Association Specialty Conference on GIS will be held in New Orleans next week. The ESRI Hydro team will be getting there early, and staying late, so if you want to say “Hi,” here’s where we’ll be:
On Sunday, March 25, Dean Djokic is leading his famous workshop on hydrologic and hydraulic modeling in GIS. This is a great opportunity to get some hands-on experience with a broad swath of GIS
applications.
On Monday, Aquaveo and the BYU team will present new developments in Arc Hydro Groundwater at 1:30, and at 3:30 there will be a discussion of World Water Online moderated by Dr. David
Maidment. WWO is an exciting new collaboration between ESRI and the University of Texas that will bring global water resource data and H&H modeling into the web. Also, don’t miss Gonzalo
Espinoza’s poster about using Mexico as a test case for the WWO framework
What is SWAT?
A sophisticated basin-scale computer model that predicts impacts of weather, soils, land use and land management on water supplies and pollution as well as soil erosion, fertility and crop production.
This model contributes to understanding the complex ecosystem and its service to water availability, water quality; food vulnerability and food production; as well as socioeconomic demography issues worldwide.
The Soil and Water Assessment Tool, or SWAT model, is a public domain model developed by a group of scientists from the USDA-Agricultural Research Service; USDA-Natural Resources Conservation Service, and Texas A&M University.
We’ve heard lots of feedback over the last few days from users who want to find the old “Insert your favorite” blog. Unfortunately the redirects we had in place when we deployed the new ArcGIS Blog pointed to its home page instead of these specific locations, leading to many unhappy readers. We have most of these redirects in place now & will have the rest completed today. If you’d rather not wait, here’s a table matching the old individual blogs to their corresponding URLs and RSS feeds in the new unified blog.
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Elevation data is an essential piece of GIS data for hydrologic applications, but it’s big, not always easy to get and for modeling surface water flow requires specialized processing to become useful. Elevation data and services are coming to ArcGIS Online, including some hydro specific capabilities.
World Elevation Services
The World Elevation Services became available for beta testing last fall and will be released at the end of March. There are image services, data download services, and analysis task services available, as well as sample applications. The services are built from a collection of data sources, ranging from less than a meter resolution up to almost 5 kilometers, and includes services of elevation, shaded relief, slope, and aspect. We will continue to add new data as it becomes available. Like other things on ArcGIS Online these services can be used in Desktop and any other Esri clients, and also in other applications via REST or SOAP. http://resources.arcgis.com/content/imagery/10.0/world_elevation
Hydrologic Services
Since you’re reading the Hydro Blog, your obvious thought is, when can I start using elevation web services for water resources applications? You’ll be happy to know we’re working on it. You’ve probably noticed a shift happening in ArcGIS Online and the Resource Centers to more specific application areas, in places like ArcGIS for Local Government and right here for Hydro.
