PrecipGen: Long-Term Precipitation Forecasting

Posted by Jason Lillywhite

A GoldSim model that simulates long-term daily precipitation (PrecipGen) has been added to the GoldSim Model Library. We applied the model to locations in Logan, Utah and Dublin Ireland to help evaluate the effectiveness of this model's ability to forecast daily precipitation rates and capture long term droughts. This application is useful for GoldSim modelers looking to incorporate randomly generated rainfall forecasts in their water balance models. The model shows promise in simulating precipitation for a site that is influenced by multi-year wet and dry cycles. Informal testing has been showing signs of robustness and some refinements to the testing are currently underway.

Figure 1 - Screen Capture of PrecipGen with Results

Simulating Daily Precipitation Using a Time Series Element

Posted by Jason Lillywhite

In GoldSim, the Time Series element serves as an effective tool to represent precipitation data. Given the versatility of this element in portraying such data, I felt compelled to share some best practices and tips for those keen on utilizing this kind of data. 

In this article, I will illustrate how to view and interact with measured daily precipitation using a Time Series element. Additionally, I will delve into some data definition properties and demonstrate the use of a Time History Result element to visualize historical trends and compute period statistics. 

This blog post aims to provide insights into modeling with time series data more efficiently, regardless of whether you are a GoldSim novice or an experienced user.

2024 GoldSim User Conference

Posted by Jason Lillywhite

We are excited to announce the return of the GoldSim User Conference, which will be held from September 9th to 11th, 2024 in the beautiful city of Seattle. September is one of the best months to visit, with an average temperature of 71F (22C). 

GoldSim user conferences provide great learning and networking opportunities for both expert and novice users. The conference will be held at the beautiful Seattle Marriott Waterfront and the adjacent Bell Harbor International Conference Center, both with stunning views of the downtown Seattle waterfront. In addition to oral presentations, poster sessions, panel discussions, and training sessions, registration also includes several fun networking events (a dinner cruise on Elliot Bay and a Seattle Mariners game in luxury suites). We look forward to seeing you in Seattle! Register now!

Simulating Controlled and Uncontrolled Reservoir Discharges

Posted by Jason Lillywhite

When simulating ponds and reservoirs in GoldSim, one of the most common types of systems we see are the combination of controlled and uncontrolled discharges. Examples of uncontrolled discharges include evaporation losses and flood flows over a spillway. Examples of controlled discharges include water that is pumped out or flows through an opening in the outlet works. Controlled outflows deliver water to service necessary uses downstream such as irrigation or industrial water demands.

In this blog post, I will walk through the process of setting up this type of model in GoldSim. Hopefully this will provide a good resource for those of you working on conceptual water balance models for your projects.

Best Practices for Modeling Interacting Ponds

Posted by Jason Lillywhite

A new demonstration video was posted that can help you improve complex water balance models. In this video, I demonstrate how we can more clearly show the flows within a complex network of ponds.

I do this by comparing the difference between directly defining flows (see image on the left) and keeping actual flows separate from requests that drive the flows (see image on the right). Following these ideas can significantly improve the visualization of the system you are trying to model, especially when you have many flows being passed between components of your system.

In-Person GoldSim Training - September 13, 2023

Posted by Jason Lillywhite

I will be teaching a 1-day hands-on GoldSim training course at the upcoming Arizona Hydrological Society's Annual Symposium on September 13 in Flagstaff Arizona. Visit their conference website for more information: GoldSim Workshop – 2023 AHS Symposium. We hope to see you there!

Improve Workflow with Shortcut Keys in GoldSim

Posted by Jason Lillywhite

The graphical features of the GoldSim user interface are highly intuitive and easy to use, making it one of the most popular simulation software tools available today. The user-friendly interface allows even novice users to quickly and easily create models, organize their elements into containers, and navigate through them using the built-in browser and navigation tools. With its intuitive interface, GoldSim allows users to focus on the task at hand rather than on the software, which ultimately leads to better results and improved productivity.

But did you know that there are many shortcut keys available that can make your modeling experience even smoother and more efficient? In this blog article, we'll explore some useful shortcut keys in GoldSim. Whether you're a seasoned GoldSim user or just starting out, these shortcuts are sure to save you time and make your modeling experience more enjoyable.

GoldSim 14.0 Revision 2 Has Been Released

Posted by Jason Lillywhite

This update includes a number of corrections, reliability improvements and general user-interface enhancements. All users are strongly advised to always use the latest Revision available. Anyone currently with access to GoldSim 14 has access to this Revision.

Linking GoldSim to Python-Enabled Excel

Posted by Jason Lillywhite

I recently presented a webinar called "Effectively Working with Excel", demonstrating some of GoldSim's Excel interface features. In addition to demonstrating how GoldSim can import/export data, I also talked about how GoldSim can dynamically interact with Excel during a simulation. One of the attendees asked me if GoldSim will wait for user-defined functions to be called by external programs, DLLs, or scripts used by Excel before reading in values from Excel. At the time, I didn't have a ready answer because I couldn't think of a time that I've actually seen this done.  

To answer his question, I built a simple GoldSim model that interfaces with an Excel file and this Excel file relies on user-defined functions written in a Python script. I thought this example might also be useful for a wider audience, so I decided to blog about it.

Simulating Precipitation with Long-Term Droughts

Posted by Jason Lillywhite

One of GoldSim's most popular models downloaded from our Model Library is the GoldSim implementation of a Stochastic Weather Generator (WGEN). This model simulates probabilistic climate that drives hydrological processes in environmental systems models, such as precipitation, temperature and solar radiation.

One of the limitations of this model is that the generated precipitation time series generated by the model doesn't account for long-term drought cycles. Using the National Integrated Drought Information System (by NOAA), we can apply the Standardized Precipitation Index (SPI) to precipitation generated by WGEN to account for droughts. This blog post summarizes an approach used to incorporate droughts for a site during the years 1910 - 2022 and found to produce results that compare well to the historic precipitation measured at a site in Manti, Utah.

The GoldSim Contaminant Transport Module Online Course is Now Available!

Posted by Rick Kossik

Over the last two years I posted six excerpts from the Contaminant Transport Module Online Course. I had promised that it was under development and would eventually be posted in full. I posted the last of these excerpts a year ago and then went silent, so you may have wondered "what happened?". With the exception of the last excerpt, these were from the (early) conceptual parts of the Course. The remainder of the Course is "hands-on" and procedural and would not have necessarily worked well in a blog format. Hence, the silence. Well, FINALLY (after 2 years of effort) the full Course is now available. In this post, I briefly provide an overview of what you can expect.

Introducing the Final Value Result: Soon Available in GoldSim 14

Posted by Rick Kossik

We have been working for the last several years on the next major GoldSim release (GoldSim 14).  We expect to release this by October 15. All users with active maintenance will receive an email at that time with instructions for upgrading.

GoldSim 14 contains a large number of changes and updates.  In this blog post, I briefly discuss one of the most noticeable new features that you will see (a new type of result display). When we release GoldSim 14, we'll post another article to the blog (as well as send out a newsletter) summarizing all of the new features and updates.

Avoiding Concentration Spikes when Simulating Cells that are Emptying (and Refilling)

 Posted by Rick Kossik

As part of the process of creating a very detailed online course for the GoldSim Contaminant Transport Module (for which a number of excerpts have been published in previous blog posts), I have been revisiting the most common questions and problems that we have been asked about by our users over the years in order to make sure to discuss these in the course (as well as to add more detailed descriptions, when warranted, in the User's Guide).

One of the more common issues that we see is the problem of GoldSim producing unrealistic spikes in computed concentrations when the volume of water (or another medium) in a Cell changes significantly over a timestep.  This most commonly happens when the Cell dries out (i.e., the volume actually goes to zero) and (perhaps) subsequently refills. There is a way to avoid this problem (which we have provided to users when the issue arises), but it is not discussed in detail in the current version of the User's Guide (which will be remedied in the next release).

In this blog post, I will first discuss the nature of the problem (when does it occur?) and how to address it in the current release of GoldSim (12.1).  For those that are interested, I will then discuss the numerical reasons for this problem, as well as an alternative approach that will be available for addressing the problem in the next GoldSim release (expected later this year).

GoldSim Contaminant Transport Module Online Course, Excerpt #5: Chemical Processes Controlling Mass Transport

Posted by Rick Kossik

This is the fifth installment of short excerpts from the online CT Course that is currently under development. These excerpts are all, by necessity, from the conceptual parts of the Course, as those parts that are "hands-on" don't necessarily work well in a blog format.  However, there is plenty of conceptual matter to discuss (the Course is very detailed and extensive), so I'm hoping you will still find these excerpts useful. 

The first excerpt simply provided the outline describing how the Course will be organized.  The second excerpt  discussed the key decisions required before starting to build a contaminant transport model. The third excerpt discussed the problem of uncertainty in contaminant transport models and the underlying philosophy of the GoldSim Contaminant Transport Module. The fourth excerpt provided an overview of the physical processes controlling mass transport (advection, dispersion and diffusion).

This excerpt provides an overview of the chemical processes controlling fate and transport.

GoldSim Contaminant Transport Module Online Course, Excerpt #4: Physical Processes Controlling Mass Transport

Posted by Rick Kossik

As I noted in previous blog posts, I am currently working on an online CT Course. In order to provide some useful material for users in the meantime, I plan to post excerpts from time to time as I slowly progress through the development of the Course.  

The first excerpt simply provided the outline describing how the Course will be organized.  The second excerpt  discussed the key decisions required before starting to build a contaminant transport model. The third excerpt discussed the problem of uncertainty in contaminant transport models and the underlying philosophy of the GoldSim Contaminant Transport Module. 

This excerpt finally starts to get a bit more technical, and provides an overview of the physical processes controlling mass transport (advection, dispersion and diffusion).

GoldSim Contaminant Transport Module Online Course, Excerpt #3: The GoldSim Contaminant Transport Modeling Philosophy

 Posted by Rick Kossik

As I noted in previous blog posts, I am currently working on an online CT Course. In order to provide some useful material for users in the meantime, I plan to post excerpts from time to time as I slowly progress through the development of the Course.  

The first excerpt simply provided the outline describing how the Course will be organized.  The second excerpt  discussed the key decisions required before starting to build a contaminant transport model. In this excerpt from one of the introductory Units of the Course, I discuss the problem of uncertainty in contaminant transport models and then summarize the underlying philosophy of the GoldSim Contaminant Transport Module.

GoldSim Contaminant Transport Module Online Course, Excerpt #2: Key Decisions Required Before Starting to Build a Contaminant Transport Model

 Posted by Rick Kossik

As I noted in my previous blog post, I am currently working on an online CT Course. This will be a long-term project (I'm hoping to finish by the end of the year).  But in order to provide some useful material for users in the meantime, I plan to post excerpts from time to time as I slowly progress through the development of the Course.  A blog is not the best venue for presenting the entire Course (even in parts), but I think it will be possible to provide a number of short excerpts that could be of value.

The first excerpt simply provided the outline describing how the Course will be organized.  In this excerpt, I present some information from a preliminary Lesson discussing the key decisions required before starting to build a contaminant transport model.

Navigation Tabs in the Dashboard

Posted by: Jason Lillywhite

If you want to add navigation tabs to a dashboard, you will need to create multiple dashboards with graphical components that align in order to give the impression that you are switching tabs instead of switching entire dashboard pages. Luckily, with a few simple steps, this is quite easy to do. Follow these basic steps to quickly create your navigation tabs for your dashboard.

We will be using Microsoft Power Point to draw the Navigation graphics for the Dashboard.

GoldSim Contaminant Transport Module Online Course, Excerpt #1: Course Outline

Posted by Rick Kossik

As many of you may know, several years ago, we posted our free online GoldSim Course.  This Course has been tremendously popular, with almost 900 registered users (and an uncounted number of users who took the Course without registering - registration is optional). The Course, however, only covers the basic GoldSim framework, and does not discuss any of the specialized modules.  Many people have expressed interest in a Course on the Contaminant Transport (CT) Module, but we have never had the time to put one together.  Creating effective online Courses is tremendously time-consuming: the basic Course took at almost a man-year to complete.

However, one advantage of the pandemic we are living through is that it actually provides an opportunity to work on some of the things we have not had time for.  In my case, it has provided an opportunity for me to spend some time on the CT Course. This will be a long-term project (I'm hoping to finish by the end of the year).  But in order to provide some useful material for users in the meantime, I plan to post excerpts from time to time as I slowly progress through the development of the Course.  A blog is not the best venue for presenting the entire Course (even in parts), but I think it will be possible to provide a number of short excerpts that could be of value.

So far, I have developed a very detailed outline and have completed the first 3 Units (out of 15). In the first excerpt, I simply provide the outline describing how the Course will be organized.  Note, of course, that things may change slightly as the Course continues to unfold!  Hopefully, this will get you excited about what is to come.

Combining a Weather Forecast with a Stochastic Weather Generator

Posted by Jason Lillywhite

A couple of years ago, I blogged about the application of the GoldSim WGEN model for producing probabilistic time histories of precipitation and temperature data. WGEN is useful for modeling natural systems impacted by uncertain climate influences. This model can also be used for simulating future scenarios and forecasting.

Even though the results of a WGEN model are probabilistic and uncertain, they are based on historical observed records and tied to the latitude of the earth. This allows us to produce realistic future simulations. But if you plan to use WGEN for short-term forecasting (less than 6 months), it might be helpful to incorporate a weather forecast for the first part of the simulation. Read more to see how a web service forecast model is combined with WGEN to produce a more reasonable forecast for a specific location without having to manually download the forecast.