Assignment 7

Perez-Pedini C, Limbrunner JF, Vogel RM (2005) “Optimal location of infiltration-based best management practices for storm water management,” JOURNAL OF WATER RESOURCES PLANNING AND MANAGEMENT, 131(6) pg. 441-448.

Summary

This essay was to look at best management practices (BMPs) based on infiltrations versus storage-based to mitigate flood and water quality damages. The objective of their model was to minimize the peak flows at the watershed outlets by determining optimal locations of the BMPs. The event-based hydrologic model used for the optimization was expanded upon the Natural Resource Conservation Services Curve Number method. This model was incorporated in Microsoft Excel, using a genetic algorithm methodology. The genetic algorithm established areas in which the BMP would be most efficiently used in order to decrease the flood flow. The topographical constraints incorporated in the model was developed by ArcGis, and then was brought into Excel. There was also curve number and slope constraints. The algorithm used for the flow direction simulation was the D8 algoritm due to simplicity.

The model was used on a watershed called Averjona River, near Boston. This was a highly urban watershed. The model was calibrated using two distinct storm events. However, the authors concluded that the output of the model was not interrelated to the observed, long term data. Therefore the authors decided that there was a problem with the groundwater storage characteristics in the formulation of the model. Another disadvantage of the model is the time step has the most control over the entire model in terms of locations for the infiltration-based BMPS. It was also found that optimal locations of BMPS were subsets of larger sets of BMPs.

Discussion

This article was interesting to me, because I think ArcGIS is a powerful tool that should be implemented when using the Natural Resources Conservation Services Curve Number method. It would make the Curve Number calculations easy, and has accurate topographical information readily available. Furthermore, this optimization model would be quite useful in practice.

Even though I’m still somewhat new to the concept of genetric algorithms, I noticed the authors noted that the D8 algorithm was used for simplicity. This could definitely be a fault of the research, and definitely something I would expand on if I were to continue this research. Also, I would like to see how the output of this infiltration-based BMP model compares to a storage-based technique. Lastly, I would conclude that this model wouldn’t be very replicable.