Aquaveo & Water Resources Engineering News

Bringing Water Stability to the World

By jcreer on November 27, 2019

A project that Aquaveo is proud to be part of is bringing forecasting data to people around the globe through GEOGLOWS.

Because many countries around the world don’t have the resources to predict droughts and floods, they struggle to keep a steady supply of food and stable economy. Companies such as the World Bank, ESRI, NASA and others have partnered together to create a warehouse of apps to predict a 15-day forecast of more than 200,000 streams across four continents to help anyone from farmers to politicians be better prepared for any changes.

Though Aquaveo only came onto this project recently, designing an API for these apps, we are very excited to be helping countries around the world such as Somalia and Ethiopia overcome their struggles to stabilize their economies, and be better prepared for disasters.

Two of Somalia’s main rivers, the Juba and Shebelle rivers, originate outside of their boundaries in Ethiopia and Kenya, which is a major obstacle for Somalia. A streamflow forecasting system helps improve water management in the country by providing much needed transboundary water information--helping them foresee flooding within days allowing them to take action.

Ethiopia gets between 40–87 inches of rain a year, both because of this much rainfall and in spite of this much rain, Ethiopia is vulnerable to floods, droughts, and chronic scarcity in several parts of the country. A streamflow forecasting system helps improve water management in the country by providing the necessary data to make decisions and develop action plans.

Since the formal creation of the initiative in 2017, the most significant element of GEOGLOWS has been the application of Earth Observations (EO) to create a system that forecasts flow on every river of the world while also providing a 35-year simulated historical flow. We can now deliver reliable forecast information as a service, instead of all the underlying data that must be synthesized and computed locally to produce the necessary information.

Aquaveo have been proud to be part of GEOGLOWS and other initiatives. Watch our website to see news about more projects like this in the future.

Blog tags:

Tethys

Best Practices for 2D Hydraulic Modeling

By aquaveo on November 20, 2019

In SMS, designing a good 2D hydraulic model from the start gives the best results. A poorly designed model can give bad results, cause model errors, or even keep the model from converging. And while it may seem easy at first to design a good model, there are plenty of potential pitfalls that can come up if you are not careful.

The following tips, broken down into five areas, can help improve any model.

Terrain Data

Pay attention to your terrain data. You can't set up a good model without a good foundation, and terrain data is your foundation. There are four things you will need to spend time getting right:

Represent hydraulic controls accurately
Make sure you include channel bathymetry
Add breaklines where needed
Finally review the terrain surface for missing features

Mesh Development

Use an appropriate number of elements: size does matter, more is not always better. This is mainly because the time your model takes to render is a significant factor for any project. Element length should generally be equal to or greater than the flow depth, except for limited areas such as piers. When elements are too small, waves can form skewing the model results.

Quadrilatereal elements in meshes are often more stable than when using triangular elements. Once you have set your number of elements and length, confirm that hydraulic controls are represented in the mesh.

Lastly, review your mesh for quality.

Boundary Conditions

When determining the boundaries of your model, you will need to find two things. First look for the most constricted area when determining model limits. Second, find the furthest usable boundary location from the area of interest. A good rule of thumb for rivers: two floodplain widths up and downstream. Note that the width of the mesh should be greater than the maximum flood width.

Lastly, perform sensitivity analysis on boundary conditions.

Material Roughness

Be aware that Manning's n values for 2D model can be lower than 1D models. Be sure to calibrate your model. Essentially check your results to see if they are reasonable.

Model Execution and Review

Use the largest time step possible that gives you continuity and stability ( i.e. while still achieving a good solution).
Use monitoring points to verify steady simulation.
Use monitoring lines to verify continuity.
Review convergence parameters to confirm conservation of mass.

Following these tips can improve any model that uses a 2D mesh. Try them out in SMS today!

Blog tags:

SMS

Tips for Flow Budget in GMS

By aquaveo on November 13, 2019

In any groundwater model, knowing how much of the groundwater is available for use determines the fate of any project planned for the area. It is often a crucial part of a model to determine an accurate water budget or flow budget. MODFLOW can calculate its own flow budget and can also make use of the ZONEBUDGET program to calculate the water budget for subregions of a model. Knowing how to use both the MODFLOW flow budget and the ZONEBUDGET program greatly enhances the value of models built in GMS.

With that in mind, here are some tips for making use of a flow budget and ZONEBUDGET in GMS:

If ZONEBUDGET is used to calculate a budget for the entire modeled area, the values for each budget term should match the MODFLOW budget except in situations where there are multiple stresses of the same kind in the same cell (e.g. a pumping well and a recharging well in the same cell).
You can confirm your approach by calculating the cumulative volumes for the entire model and seeing if they match the MODFLOW outputs.
Computer precision could be a cause of small discrepancies between the budgets produced by ZONEBUDGET and MODFLOW. ZONEBUDGET accumulates budget totals using double precision, and MODFLOW uses single precision. Because of the use of double precision, ZONEBUDGET's output should generally be more accurate than MODFLOW's; however, differences in output are not likely to be significant except for some very large models.
You can find the correct cumulative volume of water entering a given zone using the flow rate. This is done by multiplying the rate by the length of the corresponding time step.
Rates reported are for the same duration of the matching time step. Time steps stair step, so there the value is the same for the entire time step.

For an overview of ZONEBUDGET in GMS, see our tutorial and try it out in GMS today!

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GMS

Working with Large DEMs

By aquaveo on November 6, 2019

Do you have a project that requires using a large DEM? Digital Elevation Model files are a great source for terrain data in WMS. A lot of projects require using DEMs which makes it important to use the data available.

Using a large DEM file can present some complications in WMS. A large file may cause the program to slow down or have difficulty processing. So it is important to make certain to use a DEM that contains mostly relevant data and doesn’t contain an excess of nonessential information.

But how do you know if the DEM data you are pulling is enough? Is more watershed data always better?

Example of DEM in WMS with contours turned on.

Pulling in more data doesn’t insure better results. Though WMS is able to handle a massive amount of data (which is not a guarantee) the hardware in your computer may not be able to handle it. In general, a DEM twice the size of your watershed is probably sufficient for most models. More than twice your watershed size tends to just bog down the model causing you to face unnecessary wait times.

What should you do if your watershed data is not loading?

If your data is taking a long time to load try adjusting the resolution. After using the Get Data from Map tool, and making your selection in the Data Service Options dialog, you will be able to select your desired resolution in the Zoom dialog. Selecting a lower resolution zoom level should make the DEM easier to work with in WMS.

You could also try breaking up the DEM into multiple DEMs. That way your computer is not overwhelmed by trying to download one huge file all at once. Then while you’re working on your model you can turn on just the DEM(s) you need.

Third party software can be used to break up the DEM or reduce the resolution.

DEMs remain an excellent source for data for projects in WMS. Download WMS today!

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WMS