Tees river levels

[samvimes]

With the unpredictable influence of reservoirs and the barrage on the Tees, I regularly check the .gov.uk river levels website before fishing. One thing I've noticed more and more in summer is the bizarre fluctuations on the Croft-On-Tees monitor. It rises and falls quite regularly despite the monitor upstream at Broken Scar seeming very steady. By the time you get to the next downstream monitor at Low Moor (Dinsdale), the peaks and troughs are largely smoothed out and much less pronounced.

Broken Scar monitor.

Croft monitor.

Low Moor monitor.

Given that it can't be down to tides or the upstream reservoirs, does anyone know for sure what might be going on? The only thing I can think it might be is either industrial water discharge or discharge from water treatment stations from Darlington. Anyone know for sure?

[davo]

Anything to do with the Skerne entering the River maybe?

[samvimes]

Jul 19, 2022 20:27:24 GMT davo said:

Anything to do with the Skerne entering the River maybe?

Quite possibly, but why would the Skerne be fluctuating so much as to make the Croft monitor fluctuate so often in times that there's no rainfall? Where's the extra water coming from?

[Marc]

The river tees has been doing this for a while now I think it's coming from the cow green reservoir when the water comes in it seems to kill the fishing for some reason

[samvimes]

Jul 21, 2022 21:46:24 GMT Marc said:

The river tees has been doing this for a while now I think it's coming from the cow green reservoir when the water comes in it seems to kill the fishing for some reason

It can't be coming from upstream of Darlington. The monitors at Broken Scar and above have shown little variation for weeks. The Croft monitor shows peaks and troughs that are reminiscent of a tidal river, just a touch less regular. It does almost look like a twelve hour cycle, but there are some small deviations.

[Marc]

It could just be that it doesn't show much in the graph for the levels above croft my father in law is on the river most days below croft and he can see the pace change every day. It could be from somewhere else but we both think it's cow green

[kev g 1953]

Just a note:-

I fish our club waters quite often and like your father in law Marc I see the levels change, I've been in the river twice this week with chest waders on to free up one or two snags and on both occasions the river depth has Changed not a lot but enough to stop me getting to places where earlier in the week I had been.

[samvimes]

I appreciate that they do a lot of tinkering with both discharges from the reservoirs (mainly Cow Green) and raising/lowering of the barrage. I've seen such changes happen myself. You know fine well it hasn't rained for days yet the river starts rising or just flowing faster anyway. In summer, a river that has been running pretty clear (for the Tees) suddenly looks very peaty. 

The problem with what I'm seeing on the Croft monitor is that these little rises and falls happen far more often than the water releases from the reservoirs. I've also noted that the reservoir releases can be seen on the Barnard Castle, Broken Scar, Croft and Low Moor monitors when they occur. The fluctuations do smooth out somewhat as you go downstream. However, the thing to note is that reservoir releases always show well on the Barnard Castle and Broken Scar monitors.

If you use the GaugeMap site and expend the graph out to show a full month. link It's fairly obvious that they were discharging from the reservoirs at the end of Jun/early July. Every couple of days for a week the river rose without there appearing to be any rainfall. During the same period, the Croft monitor still shows loads of more regular (roughly 12 hourly) peaks and troughs overlaid on longer term fluctuations.

The reservoir tinkering (that definitely happens) doesn't really explain what's going on at the Croft Monitor to me. I feel that a (roughly) 12 hourly cycle might be better explained by a water treatment plant discharge or an industrial water user discharge, possibly into the Skerne. I wondered whether the Kielder water transfer scheme pipeline might hold the answer, if it discharged it's the Tees below Broken Scar. However, it would appear that it discharges at Eggleston. The only other thing I've read about is some fairly large scale extraction that occurs at Broken Scar (for treatment) and Blackwell (for industrial use). Perhaps both these extraction points are downstream of the Broken Scar level monitor and might explain fluctuations showing at Croft but not at Broken Scar/Barnard Castle?