The majority of urban hydrological models focus primarily on differences in the rainfall-runoff ratio between pervious and impervious area. Impervious area (as I have mentioned in a previous post), is traditionally assumed to be the major causal source of changes in the hydrological cycle associated with urbanization. Infrastructure-centric urban hydrologic models assume that water that is infiltrated or evapotranspirated before reaching drains and pipes has “exited” the system. As more and more infiltration-based stormwater control measures are implemented however, this assumption needs to be more closely examined. Are urban soils and the urban subsurface truly effectively inexhaustible in capacity? This question is particularly important when we think about multiday rain events and changes in intensity of rainfall associated with climate change.
For the past twenty years, the understanding that impervious surface cover as the main causal factor for the ‘flashier’ runoff response of urbanized watersheds, has been the major focus of integrated water-land planning. Such a view however, ignores other processes by which flashy runoff response may be induced through urbanization. Better understanding of specific runoff production processes and broader views of green infrastructure planning are needed.
We just got back from a trip to Asheville, NC. Here are some of my thoughts on their awesome downtown and arts-based revitalization.
Systems that include budgets for GI come disproportionately from the top 20% of systems, by reported CSO correction need.
Model spinup refers to the pre-production run period that you run your model for to let things equilibrate before you start testing your hypotheses. In this post, I also include some strategies I used to get my model up and running.
I started using ParFlow.CLM, a 3D variably saturated overland flow-subsurface model for my research in small urban watersheds about six months ago. In this post, I list the skills that were needed to start using ParFlow and the right attitude to have going in to this type of project.
I’ve known about the USGS’ SSURGO database for awhile. Back when I was practicing as a civil engineer, we mostly used it to define drainage groups of soil. I did a few land development suitability analyses for some conceptual projects with it too, but nothing too intense. For my current project, I needed to use it to define the subsurface conditions of an urban hydrological model. Here I present how to extract more detailed information from the SSURGO database.
A long while back, I posted an article on my more-analog-than-digital workflow. Compared to then, I now spend a lot more time on producing my own research rather than on hyper-absorption of information necessary for quals and orals preparation and research area definition in the first and second years of my PhD program. My research now incorporates both statistical and physical-simulation based hydrological modeling. While I had done a lot of work in statistical and econometric modeling in my first and second years, the physical simulation modeling requires a lot more computing power. Specifically, I am applying a 3D, variably saturated overland-subsurface coupled, high-resolution model that takes advantage of parallel computing resources. My workflow has therefore evolved to incorporate multiple operating systems and organization of a lot more information and data.
Often, taking a wider, multidisciplinary perspective on urban problems can lead to criticism of being a so-called “jack of all trades master of none” . We must reject this notion if we truly believe the urban problems are not only multifaceted, but require integrated, multidisciplinary approaches to define. The solutions must not just be combinations of the economist’s solution, the engineer’s solution, and a sociologist’s solution, just as definition of the problem cannot just come from one field. Solutions must be a synthesis, and we must believe that together, these viewpoints are more than the sum of their parts. There are great thinkers who have done this. They have successfully defined hyphenated areas of inquiry.
One key to more widespread adoption instead should be to promote citizen buy-in to the other benefits of green infrastructure: beautification, subsidized landscaping upgrades, and appeals to individuals’ social pressure to “do the right thing.” The goal should be to promote the idea that “everyone is doing it.” Social media could be a great way of getting people to talk about the availability of stormwater management programs and making them more visible.