The USGS has reviewed several gauges throughout the state and has now developed regional bankfull geometry curves. For those of us waiting for these data so that we can put them to use on projects, this is a great development. The study does have a few geographic limitations, so take note of those caveats before putting the equations to use.
Posted in geomorphology, USGS gage data, watershed analysis | Leave a Comment »
Every year, ESRI hosts its annual users group meeting in San Diego. For several years now, the day before the big conference opens, the hydro/water resources folks at ESRI host a 1 day seminar. All the videos from that one day event can be viewed here:
Updates to ArcHydro, GeoRAS and GeoHMS are provided.
Thank you ESRI!
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Earlier this year, the USGS has released a web mapping service called Streamer.
It’s a fairly straightforward tool. A user can either trace a channel upstream or downstream. From there, users can get a summary or detailed report that has some basic information such as how many states the river is in, or how many USGS gages are on the trace.
A bit more background on the tool is available here: http://nhd.usgs.gov/newsletters/News_July_13.pdf
Posted in GIS, software | Tagged gis, USGS | Leave a Comment »
AIR Worldwide has just released a special edition of it’s newsletter that highlights some of the challenges to the private flood insurance market in the US. Here they are:
“The first challenge is the market itself. Because of the U.S. Government’s heavy involvement, the private flood insurance market has not been attractive to insurance innovators and pioneers. The market still has to fully embrace flood as a peril that can be insured in a profitable way—an opportunity that AIR’s new flood model can help realize.
A second challenge is the very size of the U.S. AIR has overcome this challenge with a state-of-the-art precipitation model that couples a global circulation model with a regional numerical weather prediction model to produce realistic precipitation patterns.”
As I wrote previously, the National Academies Press released its book Mapping the Zone, a key recommendation was the acquiring high resolution elevation data (e.g. LIDAR). AIR Worldwide is adding to the conversation by taking a forward looking approach and doing it’s best to predict likely precipitation regimes.
The dynamic here is rather interesting. FEMA has changed its flood insurance premium policy in 2012 due to the Biggert-Waters act. In some case, flood insurance premiums are skyrocketing, such as in some coastal areas that were hit by Hurricane Sandy. Properties located within floodplains are also affected by this policy. Obviously, no one has a crystal ball, but I am interested in hearing what people think some trends could be with respect to existing home and new homes being built within floodplains. Historically, I would completely agree that FEMA has been heavily involved in the private insurance market. With Biggert-Waters now in affect, subsidies being eliminated and premiums going up, it’s not clear to me how large FEMA’s involvement with distorting price will be with respect to influencing flood insurance premiums. Not only will Biggert-Waters have a large effect on the private insurance market, but it seems as though there will have to be some real on the ground changes in land use. I suspect many homeowners and businesses located within a floodplain will now be motivated to take a harder look at various flood proofing measures. FEMA’s list of retrofitting measures includes raising a property’s elevation, wet and dry floodproofing, relocation, constructing levees and floodwalls and demolition. Now that premiums are increasing substantially, I’m curious to know if demolition or abandonment might become more prevalent.
The property casualty insurance market isn’t an area I’ve covered too much on this blog, but given the damage that floods induce on people and fluvial and riparian ecosystems, it seems like a topic worth some review. Currently, the Property Casualty Insurance Association of America is having their annual meeting in Boston. For Twitter followers, the #PCIAM20123 hashtag might be of some interest.
Posted in flooding, recovery | Tagged FEMA, flood insurance | Leave a Comment »
This looks like a great resource for water resource managers, urban planners and hydrologists:
Thank you to the authors Dr. Bedient, Dr. Huber, and Dr. Vieux
Posted in flooding, hydrology | Leave a Comment »
The good news is that ESRI is offering a quick and easy way for users to delineate watersheds using one of its online services in ArcGIS online. You can read about here:
The one downside is that the service is only available to users who have an ArcGIS organization account. An alternative is the functionality that is available in HydroDesktop (http://his.cuahsi.org/hydrodesktop.html). This software relies on an EPA service that for the most part works pretty well, but I’ve experienced some erroneous results from time to time when making a delineation. The upside is that the software will create a shapefile of your watershed of interest to you local disk which can be convenient.
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Dr. Andrew Simon pulls together an excellent set of ideas in this presentation:
For several years, I’ve struggled with the idea of a reference stream. He lays out some of the problems with the approach. I like how he introduces the idea of a hydrologic floodplain and a topographic floodplain. I also like how he highlights the notion that “bankfull” discharge applies to a stable channel.
One of the best questions he asks is: “How does the channel respond?” Answer: “It depends” The figure below was pulled from Janet Hooke’s 2003 Geomorphology article titled “Coarse sediment connectivity in river channel systems: a conceptual framework methodology“ I think the image does a good job of supporting Dr. Simons’ question about how a channel would respond. Clearly the spatial variability that all rivers have dictate that a thorough inspection of a site and its context within a watershed is warranted.
I also always like a presentation that goes back and explicitly states first principals in geomorphology:
Applied (Driving) Forces vs. Resisting Forces.
I was first exposed to this idea as an undergraduate at Middlebury College in the early 1990′s thanks to my advisor Jack Schmidt and it is still true as it ever was today.
I like the way Mr. Simon thinks and presents his ideas. Keeping these ideas in mind the next time a restoration project comes along would be excellent, especially at the early stages so that that all parties can better understand the river adjustment dynamics at a project site.
Posted in Excel tools, restoration, river restoration, software | Leave a Comment »