Actions from Dec 5 Meeting
Gladys Conaway, USGS
Q, What is the process for updating medium res NHD? Is it being maintained at a national level?
Answer: Yes there is a process and it is being maintained. – Anyone inquiring about the possibility of updating medium resolution data should be referred to the EPA as steward for medium resolution NHD data. The EPA will manage the updates to medium resolution content to prevent conflicts between their efforts and those from the community. Please refer anyone that has an interest in updating the medium resolution data to Tommy Dewald, dewald.tommy@epa.gov, 202-260-2488.
Q, What is the EPA policy on maintaining NHD? When will they require states to use the 24k; when it’s done?
Answer, E-mail from Tommy Dewald EPA Office of Water - EPA plans to move to high res nhd once it's completed.
Actually, EPA doesn't require states to use NHD (since there is no law or regulation that requires it), rather we strongly encourage them to use it. It does make sense to do so after all.I should not have used the word 'require' in my question. I don't think anyone at the meeting actually used that word when talking about reporting information to EPA.
I expect that EPA will try to continue maintaining the med res once hi-res is completed. We'll probably keep both. One reason is that we need catchments and flow volume/velocity to support our applications and developing these addtional data requires significant additional processing, so it will be awhile before we have it for hi res.
There are a number of water program specific guidance docs on our website that reference using the nhd to support their program goals. See: http://www.epa.gov/waters/doc/index.html
Q. Versioning – extracting historical data from the GeoDB. Will users be able to get historical data on request?
Answer, E-mail from Paul Wiese, USGS NHD Geodatabase Manager - While we have the capability to generate historical data, we have not developed a procedure to extract this data. Since almost all of the historical data in the NHD reflect qa/qc fixes rather than actual changes in the landscape, this requirement has remained a low priority. However, if Missouri has a requirement to routinely access such data, we can start to take a look at it. Also, depending on the level of technical involvement in managing NHD updates within Missouri, it may be possible to implement access to historical data on the state database.
Q. When will RIT be ported to ARCGIS? Currently the Reach Indexing Tool (RIT) is only available in ArcView via the NHDGEOinArc format. You must specify the NHDGEOinArc format when downloading subbasins from the NHD Geodatabase. EPA will port to the NHDGEO format when USGS is able to provide transaction level updates. That work has not been started.
Q. Is stream order being populated in med/high res? Yes, for medium res it is currently being computed based on the Strahler Stream Order. It is in the NHD as a Value Added Attribute (VAA) that will be available soon in NHDPlus. NHDPlus contains value added attributes including; stream order, total upstream miles, and distance to sink. Medium Resolution NHDPlus will be available by the summer of 2006. Workshops for EPA and USGS personnel will be offered in Feb, and April. It will also be offered at the American Water Resources Association (AWRA) Conference in May. For more information contact Tommy Dewald. I've attached the NHDPlus Documentation for those who are interested.
I'm waiting on getting answers to the rest of the questions.
As for workshops we can set up a 1 day hands on workshop that will cover the structure of the NHDinGeo, how to use commonly used tools available on the website, and other NHD based applications when your schedules permit. In addition, there will be more information being posted to the NHD site. I'll notify you when it becomes available.
Gladys
