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How do you get elevation figures?

I like to measure the total gradient for a trip which gives an idea of how fast the river is relative to other prospects.

So to this end, I measure the elevation from the put-in and compare it to the take-out.

I use google earth for this which is handy...but for narrow rivers and streams, it is extremely unreliable. It frequently can be off significantly with strange bumps in the rivers and the center of the river often "higher" in elevation than the shoreline.

Are there online resources that are more accurarate than google in determining proper elevations of river segments?
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Comments

  • you can buy a "waterproof" gps
    that gives elevation, I think the gps watch route is probably the way to go as they seem to be more rugged

    here's what I'm using:

    http://www.amazon.com/Garmin-Foretrex-401-Waterproof-Hiking/dp/B002EOSQII/ref=pd_sim_107_1?ie=UTF8&dpID=31I51wqOmSL&dpSrc=sims&preST=_AC_UL320_SR320%2C320_&refRID=ZBDTKEAZR8846XYEYJFT

    I have to admit though that I frequently don't wear it when things are likely to get a bit dicey. Waterproof is not the same as ww kayak proof. I've already lost one unit due to sheer stupidity. Works better for hiking than kayaking but I've used it a few times for kayaking. Ideally you want something more durable and more secure on your person for ww kayaking.

    You'll notice if you read guidebooks they list gradient in terms of feet per mile. The really good descriptions will even break down the trip, for example- "six miles at 30 ft per mile and one 1/2 mile section at 70 ft per mile" So you may not even need a gps, as someone may have already done the work for you in a guidebook.
  • In the East

    roads often track water courses. Google Maps will give an elevation track using the bicycle computer.

    Garmin maps have inclinations.

    look thru:

    https://www.google.com/#q=bicycle+touring+feet+climbed+calculator

    https://www.google.com/#q=hiking+routing+total+feet+elevation+calculator
  • best of luck
    -- Last Updated: Jun-23-16 11:25 AM EST --

    Accurate topo maps (3' or 1 meter intervals) are not often readily available. The suggestion of using your GPS at intervals makes sense and is probably a good relative guide.

    You can dig up USGS maps but the contour intervals are not that precise.

    This online viewer is fun, but contour elevations only shown in 20 meter intervals:

    http://ngmdb.usgs.gov/maps/topoview/viewer/#16/45.2843/-85.0704

  • an additional thought
    -- Last Updated: Jun-23-16 11:05 AM EST --

    I don't find trips to be faster that feature more gradient- in fact the high gradient stretches take the most time- scouting or at least boat scouting is involved, sometimes safety is set up, and catching eddies becomes common place as things get more vertical.

    Volume is also a key factor in determining speed. Generally, the higher the cfs in the riverbed, the faster you go. Others will cite the exceptions but generally its been true for me. In fact at high flows sometimes you work hard to slow things down and get them under control.

    Much easier to go faster on a run you have wired up- already know the lines and can paddle proficiently without stopping- than lets say a "new to you" run that has horizon lines and requires scouting.

    for your viewing pleasure- the local river demigods going steep-

    http://vimeo.com/90837983

    http://vimeo.com/87469542

    http://www.kayaksession.com/coal-run-1st-descent-west-virginia-steep-creeking/

  • Best for comparing same/ similar rivers
    -- Last Updated: Jun-23-16 1:18 PM EST --

    Very steep, fast rivers generally have far less volume than large, flat rivers (hey, tdaniel was expecting someone to say something about this). Current speed, and thus trip speed, is affected by a lot more than just gradient, and even a lot more than volume. If you are starting from scratch, gradient and volume won't help you much at all. If you are already familiar with the river, or a river of similar size and gradient, the combination of gradient and flow may be of some help, but more than anything, it helps just to be familiar with current speeds of various types of rivers at various stages. I doubt that you can accurately predict anything based only on gradient.

    As far as maps go, I think most parts of the country are covered by 7.5-minute USGS quadrangles, which usually have a 10-foot contour interval. Though that might not seem very accurate, it'll be quite accurate by the time you figure gradient over several miles. Any place not covered by 7.5-minute quadrangles will almost surely be covered by the older 15-minute versions, which have a 20-foot contour interval.

    I used to look at read-only copies of these maps online on a site called Terra Server, but I know there are better sites for that. I bet a search would turn up something.

  • yes
    The USGS maps are a good relative measure.

    In more developed areas one might find the data on county interactive maps.
  • My Garmin Map 76Cx...
    gives the elevation wherever you are, and you can interpolate from that.
    It will also give you the degree of it's accuracy which is usually about ten feet plus or minus.

    We were just using them yesterday in a large lake that we paddle in to see if it was above or below full pond.

    Jack L
  • Thanks for all the responses
    I looked at and actually really like the USGS maps. 10 foot contour lines aren't ideal...but I can at least work with this.

    Kind of a pain to download each map though...anybody know if there is a faster alternative then doing manual downloads from http://store.usgs.gov/b2c_usgs/usgs/maplocator/(ctype=areaDetails&xcm=r3standardpitrex_prd&carea=%24ROOT&layout=6_1_61_48&uiarea=2)/.do ?
  • mytopo.com
    I've never used the site, but years ago I heard you could print customized areas of any map. However, what I was thinking is that the work you want to do need not be done in the field. It would be better done as part of your scouting of any given trip, while at home. In that case, just do your figuring by looking at maps on your screen.

    I just went to mytopo.com, and the first and only location I called up had a 15-minute topographic map, so the contour interval was 20 feet. You might have better luck and find 7.5-minute maps for areas you are interested in. Check it out and find out. This is as much as I know about the site right now.
  • contour interval changes at
    international border so you can run over 5 or 10 contour lines depending on which side you take

    http://www.nyfalls.com/assets/maps/topo/Niagara_Falls_L43079A1_25000_geo.jpg



    http://www.youtube.com/watch?v=Ui02X9KGGjI

    sorry, couldn't resist, too much fun!
  • Elevation profile tool
    Found searching

    Streamstats basin characteristics Delaware River

    links to the subject area and Steams tats beta 4

    When downloaded has Contents page 10 :

    profile tool.

    try for the Little Sandy mall bridge !
  • Usgs guage ht
    If you google "streamflow river name". You can get streamflow reports for guage locations. Some of the gage heights are given I feet above sea level.
  • Only some sites I see
  • WHOA
    stream gauge info runs deep in DC

    http://www.google.com/#q=usgs+stream+gages+gis+data
  • try the online viewer
    http://ngmdb.usgs.gov/maps/topoview/viewer/#16/45.2843/-85.0704
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