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.

Reservoir Inflow Forecasting

Posted by Jason Lillywhite

Last month, at the annual symposium hosted by the Arizona Hydrologic Society, I presented on probabilistic reservoir forecasting using GoldSim. This model combines many existing components available in our library to forecast snowmelt driven runoff inflows to a reservoir and estimates risk of spills and/or shortages.

Applying the GoldSim WGEN Model to Generate Stochastic Weather Data

Posted by Jason Lillywhite

Now you can let GoldSim do all the heavy lifting for you when simulating weather for your next project. A new GoldSim model example in our library lets you quickly generate the input data required to run the WGEN model, which is a stochastic weather generator built in GoldSim that creates daily stochastic time series of precipitation, temperature, and solar radiation.

This model (called WGENprep) uses time series data to automatically generate the input file you need to run WGEN. The WGEN model requires a lot of statistical information in order to run it and it can be quite a project to develop these inputs. With WGENprep, you can simply input the time series, change the simulation start and end time to correspond to the time series and the model will automatically export all the WGEN input data to an Excel spreadsheet. All you have to do is start up the WGEN model and then copy and paste the data from Excel right into the WGEN dashboard. These models were recently put to the test using some observed historical time series data gathered from the Salt Lake City airport weather station, provided by the NOAA National Centers for Environmental Information website.

Annual Recurrence Interval of Reservoir Spills

Posted by Jason Lillywhite

Models are built to better inform decisions. Unfortunately, the numerous disparate outputs of statistical models are often difficult to make sense of for the decision makers and/or stakeholders. Compiling the risk of specific events potentially occurring in the future into a single variable can considerably assist the decision makers into comparing the various trade-offs between different scenarios.

One of our long-time GoldSim users, Simon Chambert of Macroscopia submitted a model to our Model Library that is helpful for those looking for the recurrence interval of an event like a pond overflowing. Both the recurrence interval and exceedence probability are computed and displayed for a given set of input parameters that describe the pond design and constraints. This example can be used for other models that need to compute an annual recurrence interval.

Using GoldSim to Simulate Projects

Posted by Jason Lillywhite

The planning and management of programs and large projects is inherently difficult, not only due to their complexity, but also because something almost always goes wrong (Murphy’s Law!). By combining the flexibility of a general-purpose and highly-graphical probabilistic simulation framework with specialized features to support financial modeling and scenario analysis, GoldSim is ideally suited as a high-level project planning tool suitable during the feasibility assessment and conceptual design phases, while the exact scope of the program is still in flux and it is critical to simulate the range of possible outcomes.

Probabilistic Risk Assessment of Space Missions Using GoldSim

Posted by Rick Kossik

Many of you are very familiar with how GoldSim has been used for many years to carry out simulations of environmental systems, such as mines, water supply systems and hazardous waste sites. However, because GoldSim was designed as a flexible probabilistic simulation system, there are many cool and interesting applications in a wide variety of other arenas.  Perhaps one of the most interesting is the use of GoldSim for probabilistic risks assessments of space missions.