Category Archives: Hydro
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.
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
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.
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
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.
By Aileen Buckley, Mapping Center Lead
ArcGIS 10.0 Service Pack 4 (SP4) for English, is now available to our users for download via the ArcGIS Resource Center. This Service Pack contains performance improvements and maintenance fixes. Here are links to the downloads:
Release Note: ArcGIS 10.0 Service Pack 4 for the other five languages (French, German, Japanese, Simplified Chinese and Spanish) will be released in the next two weeks. A follow up blog entry will be posted to announce the availability once they are ready.
For the past few years the various ArcGIS product development teams have hosted a few dozen separate blogs covering the width of the ArcGIS system. Now we have pulled those together into a single ArcGIS Blog so that you can more easily browse, subscribe to, learn from, and stay up-to-speed on the latest information from all our engineers and developers. In addition, the single blog reflects ArcGIS as a system and allows us to better tell big picture implementation stories that we couldn’t in the fragmented system.
If you do want to narrow your focus, just click a Category (under Technical Communities and Industry Communities) or Tag to see the posts for that particular area. You should find a category or tag that matches up with the subject area for each of the old separate blogs. A few may have been overlooked or thought to be unnecessary. We appreciate your feedback on specific categories or tags that should be added to help focus in on subject matter that is of interest to you. Continue reading
1.0 What does it do?
Nitrate is a commonly identified groundwater and surface-water pollutant; it poses serious threats to human health and the environment. One important source of nitrate in the environment is due to wastewater treatment using Onsite Sewage Treatment and Disposal Systems (OSTDS) (a.k.a., septic systems). To facilitate water resources and environmental management (e.g., the calculation of total maximum daily loads, TMDL), we developed an ArcGIS-Based Nitrate Load Estimation Toolkit (ArcNLET) to simulate nitrate transport from septic systems in groundwater and to estimate nitrate load from septic systems to surface water bodies such as lakes and rivers. It is a screening tool based on a simplified conceptual model of groundwater flow and nitrate transport.
We have used it to estimate nitrate load from thousands of septic systems to surface water bodies in two neighborhoods located in Jacksonville, FL, USA, where nitrate due to septic systems is believed to be one of the reasons of nutrient enrichment and an isotope study indicates that denitrification is significant. While our study includes local and global sensitivity study to identify critical parameters to nitrate concentration and load estimates as well as uncertainty analysis to quantify uncertainty in model parameters, we only describe below the basic steps of using the software for nitrate load estimation in a deterministic manner. Continue reading
A common task for agencies managing water resources is to assess how new groundwater wells will affect groundwater availability, groundwater flow, and the effect on streamflow in sensitive areas. In many cases, agencies make use of groundwater simulation models to assess these impacts.
In a previous post we described a workflow where MODFLOW models are used to estimate the effects (either the change in water levels, drawdown, or flow) of new wells or increasing pumpage in existing wells. The workflow is based on MODFLOW Analyst tools to import, edit, and run MODFLOW models and visualize the simulated results. Because the tools are developed as Geoprocessing tools we can create different workflows that combine MODFLOW Analyst tools with the standard ArcGIS tools, scripts, and other 3rd party tools.
In addition, the Geoprocessing tools can be executed on ArcGIS Server. The advantage of creating a web-based application is that you do not need to have MODFLOW or ArcGIS installed on your computer to perform an analysis and create a map. In fact, anyone with a Web browser can run the model and analyze the results. Continue reading