Author Topic: How to get Fifty plus years of Flow Data for your Hydro Site  (Read 5560 times)

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ThreeTimes

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How to get Fifty plus years of Flow Data for your Hydro Site
« on: March 22, 2015, 11:37:53 AM »
Hello folks.
I'm new to posting on the forum, but I have been directed here in many of my searches on hydropower over the past while. Recently I've searched and skimmed the entire hydro section. It has been often informative and helpful. And sometimes amusing.
I don't have much to offer that hasn't been covered, but the methods I'm about to present are potentially significant. The write-up has been quite a chore, so I hope some find it useful.
In my review of forum topics the most frequent inquiry is whether the poster's waterway has any potential for usable power. The standard answer is head times flow and how to measure these. I didn't find anyone suggesting that in big fall sites, an adequate estimate of the head can be found by consulting Geologic Survey Maps. Of course, because the contours are limited to 10 feet or greater steps (depending on the map) they are not adequate for low head sites.
However, even in low head sites such as my own the Survey maps can be very useful.
Big brother is watching our water flow and make the data available for you, your neighbors and the authorities, here:
http://www.usgs.gov/water/
I found tremendously detailed records of water flow at a gaging station 4.38 miles away, starting in 1960. Wow!
Using this data and the Survey map I'm able to extrapolate flow history for my site.
If you'd like to do the same for yours, perhaps it's best to use the above site to locate the gage closest to your hydro site. It doesn't have to be on your water way or even in your drainage area, just close enough that you expect it receives the same amount of precipitation as your site.
While you're there, explore the data available, such as daily flows, highs, lows, averages, ect. The piece of information you will need to relate all this data to your site is the total drainage area the gage covers. So, write that down.
The rest of the process is somewhat tedious, but only has to be done once and it will be useful forever. I believe Geological Survey maps can be downloaded or purchased from this site:
http://store.usgs.gov/b2c_usgs/usgs/maplocator/(ctype=areaDetails&xcm=r3standardpitrex_prd&carea=%24ROOT&layout=6_1_61_48&uiarea=2)/.do

Supplies Required:
1. Hard copy map to mark and calculate the drainage area for your hydro site.
2. Tracing paper. (Any paper you can see the map through will do.)
3. Pencil.
4. Ruler.
5. Square. (Any solid object with a 90 degree angle will do.)
Steps:
1. Locate and mark your site on the map. Using your knowledge of the terrain, follow the contours on the map to mark the high points that form the rim of the drainage basin higher than your intake or turbine site. The object is to include all the land that drains through your waterway. Mark the tops of hills and draw lines between them, that will be close enough and straight lines will help later. Also draw lines from the ends of the rims to your proposed turbine location.
2. Tape tracing paper over the map and transfer your drainage outline to it. You may want to cut this out to make it easier to work with, I did.
3. Segment your area such that it is composed of triangles. Fewer is better. Don't worry about the shape. Long and skinny. Short and fat. All good.
4. Concentrating on one triangle at a time, find the longest side. Using the base and a square draw a dotted line 90 degrees from the base to the point. Measure the length of the base and the midline. Multiply these two lengths and divide by two (2) to calculate the area of the triangle segment. Note: I measured to the closest eighth inch and recorded all results in one-twenty-eights (1/128) to keep units the same. Also if we multiply x/8 * y/8 we end up with z/64 and just changing the 64 to 128 performs (avoids) the dividing by two (2) operation. Slick! (Don't you just love math?)
5. Repeat step 4 for all triangles.
6. Add the total of all the triangles area in square inches. When the denominators are the same (common), it's easiest to add, for example: 456/128ths + 123/128ths, by ignoring the denominator: 456+123=579, until the total is done: 579/128=4 67/128 or 4.5234375. (This way it's all addition until the last one division.)
7. Find the scale on your map and convert your square inches to square miles. Mine was 1:24,000 and a quarter inch (1/4") equals approximately 520 feet, a tenth (1/10) a mile.
8. Divide your total square miles by the gaged drainage square miles given on the data site. This is the factor you can use to convert the flow data on the web site to flow data for your site.
9. For example: (Reported flow data point) * factor = (your flow data point)
Questions? No. Good. Have fun. Figure out what the flow was on your birthday, your anniversary, during hurricane Sandy or the day the driveway flooded!
You finally have the information you need to figure if your site has usable power and how best to use it if it does.
And if it turns out there isn't usable power, you'll still be able to give a definitive reply to any well meaning visitor that exclaims, "You should do something to generate electricity with that water!"
ThreeTimes

SparWeb

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Re: How to get Fifty plus years of Flow Data for your Hydro Site
« Reply #1 on: March 23, 2015, 08:20:21 PM »
Hey look at that - a very useful resource of information.



Thank you very much for sharing this.

It is much like the wind resource maps that ultimately come from NOAA data (in the USA).  I bet there's an equivalent for me in Canada (I just never thought of looking until now).
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

SparWeb

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Re: How to get Fifty plus years of Flow Data for your Hydro Site
« Reply #2 on: March 23, 2015, 08:21:10 PM »
How could I forget:   WELCOME TO FIELDLINES!  :)
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

ThreeTimes

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Re: How to get Fifty plus years of Flow Data for your Hydro Site
« Reply #3 on: April 02, 2015, 11:45:08 AM »
SparWeb: Thanks for the welcome and positive comment. The graph sure is pretty and would be great for visual presentations.

I picked this forum because it was the most active with any hydro segment.

I was hoping to provoke a discussion about why this technique is easier and yet, so much more reliable than the standard techniques for measuring flow.

Most of us probably prefer stomping around our land to pushing a pencil and doing math. However, it doesn't matter when or how often the flow measurements are taken, they will never be as comprehensive as those available on the government site. No more than several hours work for any site and many thousands of flow measurements are there for use.

Yes, those graphs sure are pretty and impressive. However, I found the tables more useful. We decided we wanted a system capable of producing power nine months of the year. Using the tables, I was able to order the average month flows and determine what the flow has been for the ninth best month. First, they told me we have plenty of resource to meet the goal. Now, I am using those numbers to design our system.

See my other topic for more site evaluation techniques.

ThreeTimes

SparWeb

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Re: How to get Fifty plus years of Flow Data for your Hydro Site
« Reply #4 on: April 03, 2015, 10:17:35 AM »
Ah, but stomping about in the mud is exactly what many of us signed up for!  :)
I don' t have hydro (just wind) but who know? Someday I may live near a suitable stream so I keep my ears open.

The value of a resource like that must be tempered with careful examination of a specific site.  Both must factor into a judgement that a site is suitable.
The same goes for wind in fact.  There are Wind Energy Atlases for the US and Canada, which are great, but the level of detail in the data only suggests areas at a resolution of about 1 square mile.  The exact site where the wind turbine may go could have trees, buildings, or flat open fields all around, none of which would figure in the Atlas data.  Same goes for solar, using a reference like PVWatts.
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

ThreeTimes

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Re: How to get Fifty plus years of Flow Data for your Hydro Site
« Reply #5 on: April 03, 2015, 10:41:25 AM »
...The value of a resource like that must be tempered with careful examination of a specific site.  Both must factor into a judgement that a site is suitable...
Thanks for your reply.

What you say is true, but unlike the wind and solar resources, this water flow data is not well known yet should be part of every turbine seller's site evaluation methods.
Further, the data is very specific to a waterway and time period. Every hour for the last 54 years.
Using my techniques one can be confident of how much water and when was/will be available to produce power.
Harvesting a known resource becomes an engineering and construction challenge.

ThreeTimes

DamonHD

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Re: How to get Fifty plus years of Flow Data for your Hydro Site
« Reply #6 on: April 03, 2015, 11:22:12 AM »
Surely no two years are identical hydrologically anyway, and bigger changes are afoot also.  Ask a Californian about river flows compared to normal...?

Rgds

Damon

SparWeb

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Re: How to get Fifty plus years of Flow Data for your Hydro Site
« Reply #7 on: April 03, 2015, 11:37:41 AM »
Anyone interested in setting up a hydro power system might start measuring only when plans come together to have the system.  A decision based on interest and opportunity (important in and of themselves) but may be lacking in facts.  Having measurements going back many years rather then a handful of spot estimates is the value.

I'm still thinking about site selection issues, but I'm distracting myself from the fact that this source of data stands on its own.   It would be interesting to see how many California watersheds are making new Low's on the charts this year.  Like, Zero.
No one believes the theory except the one who developed it.  Everyone believes the experiment except the one who ran it.

System spec: 135w BP multicrystalline panels, regulated by Xantrex C40, DIY 8ft diameter wind turbine, regulated by Tri-Star TS60, 800AH x 24V AGM Battery, Xantrex SW4024

ThreeTimes

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Re: How to get Fifty plus years of Flow Data for your Hydro Site
« Reply #8 on: April 03, 2015, 12:04:16 PM »
Yeah, if I were located in a drought area, hydropower would be lower on my list. Quite the opposite is the case. We're in a valley with shorter solar days and sheltered winds. However, our quarter mile of road frontage runs along a brook feeding into a small river. I did a hydro study with a focus on potential for flooding before closing on the property.

Anyway, I suspect that others who knew about the data simply didn't have the experience to know how to make it relevant to a specific site other than where the measurements are recorded. Without this, the data isn't helpful.

ThreeTimes

thirteen

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Re: How to get Fifty plus years of Flow Data for your Hydro Site
« Reply #9 on: April 03, 2015, 12:21:22 PM »
I was looking at putting in a hydro system on one of the creeks that are on my property. But i have changes creeks this year. I have had no snow on the ground since January 6. The creek i was cleaning up and marking  for my hydro is about what August is for a flow. Small to none. But I only 46ft of fall and I would have 1200 ft pipe. First year this has happened in at least 30 years according to the local historian. I really only would need the water during the winter months when I have no real sunlight. I'm putting up solar panels this summer. I usually have two feet of snow in my yard in the first part of March. So plan ahead for low water. 13
MntMnROY 13

ThreeTimes

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Re: How to get Fifty plus years of Flow Data for your Hydro Site
« Reply #10 on: April 06, 2015, 08:58:36 PM »
... First year this has happened in at least 30 years according to the local historian... 13
The beauty of the water flow data is you don't need to depend on anyone's recollection. Go find out what the recorded history has been for your site. Then you can compare how the results match up to your needs.
We have Net Metering available here, so our design criteria is to make power nine months of the year. When that happens isn't an issue.
ThreeTimes