Scottish River levels information on SEPA web site

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pickenjohn
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Scottish River levels information on SEPA web site

Post by pickenjohn »

I have just written to SEPA, the Scottish Environment agency about the excellent river levels information given on their web site for Scotland. I have asked for the following additional information for each river:
1 an estimate in cubic meters per second of the flow of the river at different levels
2 the amount of time each level is exceeded as a percentage.
Clearly these would best be done as a graph. However I did suggest that additional columns in the new illustration they have for each river showing the range and their assessment of normal - high would do.

If anyone wants to join in asking then now might be a good time and at least the request is logged.

I wrote:
Firstly congratulations on the river levels information. It is a superb resource. Thank you.
The following information would make it even more useful if it can be added:
1: the flow at each level in cubic meters per second
2: the percentage of time a flow level is exceeded.
These could be given within the chart you have introduced on the right of the page for each river. So for example on the N Esk at Logie Mill the chart has a column from 0 to 4 showing an estimation of normal and high levels. The cumecs could be given as a figure beside that 0 to 4 column. Then in another column could be given the % of time this is exceeded: so 100% at the bottom drops to 0 or 1% or whatever at the top.
These would of course be best graphed but the current column illustration would suffice.
I believe many people would find this of interest and as a canoeist and spectator of rivers I certainly would value that information.
The cumecs I realise is an estimate and the length of time a level exceeded will be within the definition used by SEPA and this may differ for different rivers. However it will still be indicative.
Hope you can incorporate this info over the next year or so.
In the meantime thank you very much for this superb facility. It is greatly appreciated, especially now that it covers many more recording stations.
Yours
John Picken

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Jim
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Re: Scottish River levels information on SEPA web site

Post by Jim »

Hi John,

I am sure we discussed these aspects when they first made the gauges available - unfortunately most of the gauges are not flow gauges just height gauges, and are located in the natural watercourse where the cross section is not regular and likely to change from season to season due to natural erosion processes or conversely by silting.

It would be great to know the actual flow rates (and that should be possible at dam locations) but I suspect not really feasible for the majority of natural run whitewater rivers.

Good to see you are still campaigning though!

Jim

pickenjohn
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Re: Scottish River levels information on SEPA web site

Post by pickenjohn »

Hi Jim
Thanks and yes they are height gauges. That is why flow estimates would be useful. My understanding from discussions with SEPA is that they do have estimates of flow which they use for height gauged sites. Clearly these are estimates but from a paddling perspective I believe these estimates will be sufficiently indicative.

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Re: Scottish River levels information on SEPA web site

Post by jmmoxon »

Kayakers own estimates of difficulty at the different heights are more useful than knowing the volume, which means very little to most paddlers.

Mike
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Re: Scottish River levels information on SEPA web site

Post by Jim »

Mike - in time paddlers will get to understand the flow rate as well or better than they understand the height data at present. If all the gauges were available online the flow data for a catchment can be more meaningful. An example I like is the Orchy, a river with many small tributaries, and Loch Tulla providing a steady base flow. The kayakers guage is near the top of the river, the electronic one just beyond the normally paddled section, but the character of the river does chance considerably depending on whether the burns are in flood, and even then it makes a difference whether it is the eastern burns or western, upper or lower.

IF there were flow gauges on all the tributaries (there aren't and it would be too mauch data for SEPAs feed) we could sum the flows at each rapid and get a really good idea how big each one is going be. You can't sum the heights because the cross sections of each tributary and the main river are different, so 1 foot of water in one trib may be 6 inches in another and 1/2 an inch in the main river. Flows you can add and once each rapid is calibrated by flow it would be possible to understand some of the WTF days, like when you get on an about a foot, Chicken Chute feels like a 2 foot level and Eas A Chataidh feels more like a foot again - all because the reference levels we associate with trips don't really tell us anything at all about different rapids, and it may be that whilst the flow from the Allt Kinglas swells the river early making it feel bigger than the bridge gauge suggests, lack of flow from later tribs and the total flow spreading as the river gets bigger, can mean that later rapids feel smaller....

The Orchy can't be the only example of this, but I have paddled it enough to have spotted the discrepancies!

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bigbird
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Re: Scottish River levels information on SEPA web site

Post by bigbird »

In the US, it's all about flow rates, and it is a better indication, as John points out....take a look at dreamflows for example...http://www.dreamflows.com/flows-canv.php
We all just need to learn the lingo
Cheers
Iain

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Re: Scottish River levels information on SEPA web site

Post by Peter Brown »

Given the gauges are on the phone network it's a shame you can't get live levels via some sort of text message system or something.

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Easan
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Re: Scottish River levels information on SEPA web site

Post by Easan »

Personally I find the height information enough of a steer to build a picture of whats happening in the area (esp if combined with rainfall radar data), and for many years wanted
far more rivers added to the SEPA site. The recent addition of rivers and burns has been brilliant.
But I'm enough of a geek to also want flow data.
One thing I have noticed from a recent spate (no pun intended) of trib bashing I have been doing, is the number of mini guages and telecom boxes on relatively tiny burns in remote and obscure locations.
These are, I'm guessing, funded by the private sector to evaluate potential for small scale Hydro. There is a consultancy local to where I live who have a big part in the installation and operation of
these guages. I assume to assess the potential for Hydro of any scale, they need flow data, and the location for installation of these boxes is always on the natural river profile (ie not weirs) and not completely random. If the data they collect is good enough to make economic decisions, then it would be good enough for us kayakers.
Similarly, SEPAs choice of location for monitoring stations must have had a degree of assessment (areas of low erosion / deposition potential) and would only need minimal checking to ensure
calculations of flow based on heights and typical profile remain consistant.
If only we could tap into the info from the private sector.......

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Re: Scottish River levels information on SEPA web site

Post by Halox »

Not sure why you want flow rates etc. The height gauge is more than enough to guide the state of a river. If you don't know the river then a flow is useless. If you know the river then the height gauge should be enough.

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Adrian Cooper
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Re: Scottish River levels information on SEPA web site

Post by Adrian Cooper »

I'm guessing that SEPA do know the flow rates relative to the height gauges. This must be essential information for understanding flood risk.

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Re: Scottish River levels information on SEPA web site

Post by Halox »

Adrian Cooper wrote:I'm guessing that SEPA do know the flow rates relative to the height gauges. This must be essential information for understanding flood risk.
Why? Surely if the minimum height of the banking is 6 foot on the SEPA gauge then if approaches that the risk is getting close, over that then it floods.

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Re: Scottish River levels information on SEPA web site

Post by Jim »

Halox wrote:
Adrian Cooper wrote:I'm guessing that SEPA do know the flow rates relative to the height gauges. This must be essential information for understanding flood risk.
Why? Surely if the minimum height of the banking is 6 foot on the SEPA gauge then if approaches that the risk is getting close, over that then it floods.
I already explained why flow rates are more useful because it allows you to calculate the cumulative effect of tributaries.
Your approach requires the same pattern of level change over the entire catchment to have any kind of repeatable meaning. Due to the extensive nature of larger river system cathments, the highly localised nature of the Scottish weather and changeable ground conditions, these patterns can change a lot.

SEPA need to be able to predict flooding far enough in advance to alter flow control schemes, issue sandbags and evacuate vulnerable properties, that requires a bit more than noticing the level is almost up to the top of the bank.

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geyrfugl
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Re: Scottish River levels information on SEPA web site

Post by geyrfugl »

For the gauges that are in the NRFA (National River Flow Archive, I think) you will find a graph relating stage (gauge height) to flow rate. Quite often there is an empirical formula to generate the graph, which is a lot more useful, as the graphs are reproduced rather small. This goes for the EA gauges as well as the SEPA ones, of course. The site also has a lot of statistics like percent exceedances, too, and often annual flood hydrographs for a number of years. All useful stuff if you are interested enough, but not so useful when the guidebooks just tell you that the river is best paddled when the SEPA gauge is over xxx metres, which is exactly how they have been calibrated for the UKRGB community :-)

The issue is finding the data - the NRFA use a completely separate set of identity numbers for the gauges from the EA/SEPA ones. So, for example, the Nith at Drumlanrig reports SEPA gauge at http://www.sepa.org.uk/water/river_leve ... &lc=133154, while the NRFA data are at http://www.ceh.ac.uk/data/nrfa/data/station.html?79006. I have a (huge) table relating these for all the gauges I've been able to find out about, and it is almost free of errors and typos - I'll try to finish the job and put it somewhere accessible if no-one else knows of a similar facility...

OK, I've put the list up at
http://pennine.ddns.me.uk/riverlevels/ConciseList.html

It's a big page, and our broadband is flaky, so it might be most useful if you right click on that link and save it to your own computer - you might take a few goes to get it all (our internet is dropping every five minutes some days...). I'll put it somewhere with a bit better availability when I have time to fix the last few bugs I know about.

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Adrian Cooper
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Re: Scottish River levels information on SEPA web site

Post by Adrian Cooper »

Halox wrote:
Adrian Cooper wrote:I'm guessing that SEPA do know the flow rates relative to the height gauges. This must be essential information for understanding flood risk.
Why? Surely if the minimum height of the banking is 6 foot on the SEPA gauge then if approaches that the risk is getting close, over that then it floods.
What Jim said.

Fine knowing what the level in a trib is for that single location or length of river but in order to know what effect that trib will have on the collector river, the flow rate of both the trib and the collector is essential.

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