Andrew defines phosphates, and explains why they are such an issue in the Somerset Levels: the causes, the effects, what has been done to date to reduce problem, and what remains to be done
Last updated
Video Timeline (min:sec):
==================
00:00 - 44:33 Presentation
44:33 - 53:57 (end) Q & A
no chat in this session
The meeting covered various topics, beginning with technical discussions and bidding concerns before delving into the main subject of phosphate pollution in Somerset waterways. Andrew, the primary speaker, explained the causes and impacts of high phosphate levels in rivers and soil, including the effects on local ecosystems and wildlife. The group discussed potential solutions, monitoring efforts, and the roles of various stakeholders in addressing the phosphate issue, with a focus on the importance of understanding the science behind the problem and the need for continued research and action.
Actions:
Andrew to continue monitoring phosphate levels in the River Parrett and its tributaries.
Andrew to analyze data from the new environmental agency station in Langport.
Andrew to follow up on the impact of Wessex Water's recent improvements on phosphate levels.
Andrew to investigate the effectiveness of flood alleviation schemes in reducing phosphate levels.
Andrew to research the potential of willow cultivation as a phosphate-reducing crop in the Somerset Levels.
Wessex Water to continue monitoring phosphate output from their sewage treatment plants.
Environment Agency to continue managing water levels and sluices in the Somerset Levels.
Andrew Shares Background on Phosphate
Graham, Andrew, and Tristram discussed the issue of phosphate in the Parrett catchment area. Andrew shared his background and how he became involved in the issue, mentioning his work on the Martock Neighborhood Plan. He also highlighted the importance of understanding the basic science behind the phosphate issue, emphasizing that it is different from other cycles like carbon and nitrogen. Andrew also mentioned his ongoing work with universities on the issue and shared a photograph of a Somerset moor, West Sedge, which is a Ramsar site. He ended the conversation by showing a footprint of a water vole, which he has been tracking in the river Parrett for the past two years.
Oxygen Solubility and Aquatic Life Impact
Andrew discussed the issue of oxygen solubility in water and its impact on aquatic life. He shared his experience as a garden guide at Stourhead, where he witnessed the negative effects of eutrophication on a lake. Andrew then shifted the discussion to the long-term decline of the Somerset levels, which were declared a Ramsar site in 2016 due to ecological issues. He explained the nutrient neutrality programs implemented in Somerset, based on two assumptions: the SAGIS model for predicting phosphate levels and the assumption that the river Parrett and its tributaries deliver most of the phosphate to the Somerset levels. Andrew expressed his disagreement with these assumptions and hinted at a more detailed discussion on the topic.
River Parrett's Impact on Somerset
Andrew discussed the catchment area of the River Parrett and its impact on the Somerset Levels and Moors. He explained that the river's flow is restricted by levees, which were constructed by monks in the 13th century to prevent flooding. Andrew also mentioned the decline in dragonfly populations and the efforts of local people to monitor and protect the wetlands. Graham asked about the relationship between the tide and water pumping, to which Andrew responded that the pumping is affected by the tide and river levels, leading to occasional floods.
Phosphate Concentration in Rivers Discussed
Andrew discussed his research on phosphate concentration in rivers, noting that it tends to be higher in summer. He clarified the difference between measuring phosphate and phosphorus, and the importance of understanding the units of measurement. Andrew also explained that the high phosphate flow in winter is not coming from tributaries, but rather from the sediment in the river, which releases phosphate when stirred up. Tristram asked for clarification on the units of measurement, which Andrew confirmed were related to the concentration and flow of phosphate in the river.
Phosphate Buildup in River Sediment
Andrew discussed the issue of phosphate buildup in river sediment, which has been exacerbated by sewage works over the past century. He explained that the concentration of phosphate in the river is directly related to the amount of sediment stirred up by water flow. Andrew also mentioned that his colleague is conducting a similar study further downstream. The team is hoping to see a decrease in phosphate levels over the next year or two, but the exact timeframe is uncertain. Graham asked about the desirable level of phosphate concentration, to which Andrew responded that it should be around a tenth of the current level. Tristram suggested the possibility of removing phosphate from the sediment, but Andrew explained that it is very firmly bound and not easily removable. Graham asked about the impact of this issue on the sea, but Andrew admitted he did not know the answer. Cllr suggested measuring turbidity and comparing it to the amount of phosphate to track the decrease in phosphate levels. Andrew agreed, noting that turbidity does change but settles down quickly.
Water Quality Monitoring Challenges
Andrew discussed the challenges of monitoring water quality due to budget constraints and the need for daily or even hourly measurements. He mentioned that the environment agency used to conduct monthly checks but now relies on citizen scientists. Andrew also highlighted the role of farmers in maintaining water quality, noting that most around him follow Defra rules. He shared that the environment agency has successfully prosecuted two farmers for pollution, using the data collected by Andrew and his team. Graham and Tristram participated in the discussion, asking questions and seeking clarification on the process and implications of the findings.
Phosphate Concentration in Local Water Bodies
Andrew discussed the issue of phosphate concentration in local water bodies, particularly in flood alleviation ponds and the River Parrett. He noted that the pond, despite being fed by a phosphate-rich stream, had very little sign of phosphate after a few days. He also mentioned that the River Parrett, which flows into Langport, has a higher concentration of phosphate due to the floodwater picking up phosphate from the fields. Andrew suggested that the artificial maintenance of the flood levels could potentially reduce the phosphate concentration. Tristram asked a question about the water to the right, which Andrew clarified as flood prevention water that acts like a pond, potentially reducing phosphate levels. Andrew also mentioned that he is studying the effect of the water draining away on the phosphate concentration.
Addressing Somerset Levels Problem
Andrew discussed the potential causes of the levels problem in the Somerset area, suggesting that it might be a global warming issue rather than a simple phosphate problem. He mentioned that the previous year's drought had exacerbated the issue, but this year's rain had somewhat alleviated it. Andrew also talked about potential solutions, such as growing willow, which could help remove phosphates and possibly serve as a high-end economic crop or be used as fuel. He invited questions and passed the screen to Graham for further discussion.
Addressing High Phosphate Levels
Graham and Andrew discussed the issue of high phosphate levels in the soil and water, particularly in the context of farming practices. Andrew explained that the high levels of phosphate in the soil assist in the growth of crops, but also contribute to water pollution. He mentioned that the sewage treatment works have improved their filtering process, but the problem persists due to the high phosphate levels in the slurry from large farms. Andrew also mentioned a new company developing a process to remove phosphate from small streams. Graham expressed interest in the topic and the potential solutions. Tristram clarified that the problem is not solely due to the sewage treatment works, but also due to the farming practices. The conversation ended with Andrew expressing his hope for a significant improvement in the first year of the new sewage treatment works.
WEBVTT
136 00:09:39.290 --> 00:09:43.260 Graham Stoddart-Stones - Great Collaboration: By all means, Andrew, Take over the meeting, please.
137 00:09:43.260 --> 00:09:46.260 Andrew Clegg, Martock: Okay, let's so I'm going to share
138 00:09:46.620 --> 00:09:49.360 Andrew Clegg, Martock: the screen. Now, if it works.
139 00:09:51.260 --> 00:09:54.919 Andrew Clegg, Martock: No, that's the wrong one. That's the right one share.
140 00:09:56.490 --> 00:09:58.709 Andrew Clegg, Martock: Now, you should be seeing.
141 00:09:58.710 --> 00:09:59.150 Graham Stoddart-Stones - Great Collaboration: Yeah, we can.
142 00:09:59.970 --> 00:10:06.450 Andrew Clegg, Martock: My my presentation phosphate in the Parrett catchment.
143 00:10:06.830 --> 00:10:07.470 tristram cary Winchfield Parish: Yep.
144 00:10:07.470 --> 00:10:16.779 Andrew Clegg, Martock: I wonder if I can shift it so that all right, I'm just going. I've got 2 screen. That's better. I'm going to shift all you people from
145 00:10:16.880 --> 00:10:18.800 Andrew Clegg, Martock: the right hand side to the left.
146 00:10:19.530 --> 00:10:25.030 Andrew Clegg, Martock: Okay, that is a photograph of a Somerset moor.
147 00:10:25.880 --> 00:10:37.769 Andrew Clegg, Martock: It's it's it's only 5 metres above sea level. It's not like the conventional moors which are high up. The Somerset Moors are very low. This is this is West Sedgemoor.
148 00:10:38.461 --> 00:10:49.150 Andrew Clegg, Martock: I just put it there as an introductory slide, just to show you that I'm not working alone in this for phosphate issue. There's other people
149 00:10:49.843 --> 00:10:57.219 Andrew Clegg, Martock: working with it with it, including a couple of universities. So it's quite a a large issue.
150 00:10:58.213 --> 00:11:02.980 Andrew Clegg, Martock: But there is West Sedge Moor, the biggest of the Moors.
151 00:11:03.490 --> 00:11:06.070 Andrew Clegg, Martock: It's a Ramsar site in itself.
152 00:11:08.140 --> 00:11:11.150 Andrew Clegg, Martock: Next slide. This is a little bit about me.
153 00:11:12.050 --> 00:11:15.790 Andrew Clegg, Martock: and what I want to do is to to show you these little footmarks.
154 00:11:16.060 --> 00:11:17.619 Andrew Clegg, Martock: Do you know what these are.
155 00:11:21.330 --> 00:11:22.410 Andrew Clegg, Martock: Anybody.
156 00:11:23.010 --> 00:11:24.249 Cllr Stuart Withington, Gt Dunmow-TC, Essex: Looks like a bird.
157 00:11:24.600 --> 00:11:29.509 Andrew Clegg, Martock: No, that is the fore print of a water vole.
158 00:11:30.330 --> 00:11:55.009 Andrew Clegg, Martock: and I'm putting it in, because when I was a child in Yorkshire, as soon as we approached the stream, the stream, our local stream there was plop, plop, plop, plop! As all the water voles jumped in and swam away. These days. It's rare, and this one is in the mud next to where I have been taking samples in the river Parrett for the last 2 years.
159 00:11:56.640 --> 00:12:03.990 Andrew Clegg, Martock: I just want to mention this last issue. Here I was. I guided Martock neighborhood plan could
160 00:12:04.290 --> 00:12:10.610 Andrew Clegg, Martock: through to fruition, and within a couple of weeks it was declared out of date.
161 00:12:10.630 --> 00:12:23.819 Andrew Clegg, Martock: That's the official planning. Speak for you don't have to take any notice of it. And the reason was that South Somerset could no longer show a 5 year
162 00:12:23.820 --> 00:12:41.090 Andrew Clegg, Martock: housing land supply, because they said of the phosphate issue, and I thought, Well, what on earth is this issue that has? I've wasted 3 years of my life only to produce a plan that is now out of date. So that's what started me off
163 00:12:41.220 --> 00:12:51.889 Andrew Clegg, Martock: looking at the phosphate issue in in this area? Can I do a quick skip through 3 slides which are basic science actually. But important
164 00:12:52.550 --> 00:12:55.220 Andrew Clegg, Martock: phosphate goes around and round in nature
165 00:12:55.360 --> 00:12:59.979 Andrew Clegg, Martock: like everything else. It's recycled. But I want to look at this
166 00:13:00.650 --> 00:13:21.990 Andrew Clegg, Martock: because phosphate is different from all the other things, like carbon and carbon, cycle and nitrogen cycle, and so on. In that the phosphate, the reserve of phosphate, is stuck in the soil, and I mean stuck because phosphates are extremely insoluble.
167 00:13:22.240 --> 00:13:30.489 Andrew Clegg, Martock: particularly aluminium phosphate, which you get a lot of on the Somerset levels because it's clay and clay contains a lot of aluminium.
168 00:13:30.600 --> 00:13:37.169 Andrew Clegg, Martock: So phosphate tends to stick hard to soil. It doesn't get washed out easily.
169 00:13:39.320 --> 00:13:44.510 Andrew Clegg, Martock: But otherwise it does recycle next one.
170 00:13:45.880 --> 00:13:52.689 Andrew Clegg, Martock: which I think is actually much more important than the probably the most important issue here.
171 00:13:54.110 --> 00:13:57.130 Andrew Clegg, Martock: In that oxygen
172 00:13:57.719 --> 00:14:09.959 Andrew Clegg, Martock: or it is soluble in water, but it's much more soluble in cold water, 0 temperature much more soluble than at the summer temperature here.
173 00:14:10.460 --> 00:14:28.009 Andrew Clegg, Martock: you see, so that as the water gets warmer, oxygen diffuses out of the water and the war, and and by the time we get to about here. Anything living in the in our waters is having a bit of trouble.
174 00:14:29.106 --> 00:14:43.179 Andrew Clegg, Martock: And that the oxygen levels in the waters tend to be replaced by plants growing in the water and photosynthesizing below the surface of the water and replacing the oxygen all the time.
175 00:14:44.327 --> 00:14:51.059 Andrew Clegg, Martock: So water organizes organisms find it difficult to survive as the water warms.
176 00:14:51.340 --> 00:14:54.749 Andrew Clegg, Martock: and they need help of these underwater plants.
177 00:14:57.280 --> 00:14:59.420 Andrew Clegg, Martock: Anybody know Stourhead?
178 00:14:59.930 --> 00:15:00.650 Graham Stoddart-Stones - Great Collaboration: Yes.
179 00:15:00.820 --> 00:15:11.210 Andrew Clegg, Martock: It's a very fine. So where the landscape garden movement started and I'm a garden guide in Stourhead. And I took this photograph in July 2018.
180 00:15:11.730 --> 00:15:14.799 Andrew Clegg, Martock: This is the main lake. It looks like a cricket pitch.
181 00:15:15.440 --> 00:15:26.000 Andrew Clegg, Martock: and this is what happens when things get out of control. There's a lot of nutrients in the water. This blanket algae grows.
182 00:15:26.130 --> 00:15:47.350 Andrew Clegg, Martock: covers the surface of the water. No light can get in, and so you can't get any any photosynthesis under the water, the water gradually suffers from oxygen, starvation, and things begin to die. It's made worse when the alga dies, because that uses up more oxygen in
183 00:15:47.380 --> 00:15:59.399 Andrew Clegg, Martock: in decomposing. And you get this. This is a process called eutrophication. Basically, after a while, Stourhead Lake. After a couple of weeks like this, it begins to really stink.
184 00:16:01.210 --> 00:16:09.800 Andrew Clegg, Martock: So that's what what eutification is. And that's what that that is the worry about what's happening to the Somerset levels.
185 00:16:10.840 --> 00:16:12.799 Andrew Clegg, Martock: And you get this kind of thing.
186 00:16:14.365 --> 00:16:17.129 Andrew Clegg, Martock: Took this photograph a couple of years ago.
187 00:16:17.933 --> 00:16:23.686 Andrew Clegg, Martock: A Rene, I it's pronounced Reen. RHYN e
188 00:16:24.470 --> 00:16:29.389 Andrew Clegg, Martock: not Rhine, Rhine in Somerset. I think it's Rhine in Wales, or something like that.
189 00:16:30.472 --> 00:16:36.520 Andrew Clegg, Martock: It's this is these are. This is West Sedgemore. It's fed by local streams.
190 00:16:36.580 --> 00:17:01.170 Andrew Clegg, Martock: The water flows around. But the problem is that there's very little flow happening, because the water now is pumped out of the of the moor, and in the hot weather there isn't any water left to pump out, but water still gradually comes in from streams nearby
191 00:17:01.290 --> 00:17:13.239 Andrew Clegg, Martock: evaporates, and any phosphate then gets concentrated in the water. So this is what happens on a on a hot year. This is the drought, the drought year of summer. 22.
192 00:17:13.859 --> 00:17:37.110 Andrew Clegg, Martock: And down here this is. These are all thousands of water snails upside down. They've come to the surface to try and get a gasp of of oxygen from the air, and they come up with their foot to the surface and breathe in that way. That's a sign of really stressed stressed somerset levels.
193 00:17:37.570 --> 00:17:40.500 Andrew Clegg, Martock: So let's go to the main issue. Now.
194 00:17:42.112 --> 00:17:53.619 Andrew Clegg, Martock: The long term decline on the Somerset levels, which are UN sites ramsar sites. It was declared illegal in, I think, about 2,016
195 00:17:53.920 --> 00:17:57.569 Andrew Clegg, Martock: by the Supreme Court, then, which is then the European Court.
196 00:17:58.413 --> 00:18:07.990 Andrew Clegg, Martock: Because of the ecological state, the the countries that had such ramsile sites in Europe, and we're not the only one Netherlands also had. Some
197 00:18:08.250 --> 00:18:13.009 Andrew Clegg, Martock: were letting them letting them decline and weren't, weren't doing anything about it.
198 00:18:13.450 --> 00:18:20.269 Andrew Clegg, Martock: And and it was, it was felt that the high levels of phosphate throughout the levels were the main problem.
199 00:18:20.460 --> 00:18:29.969 Andrew Clegg, Martock: And so nutrient neutrality programs had therefore, by law to be included with all future planning.
200 00:18:30.640 --> 00:18:35.109 Andrew Clegg, Martock: So if you wanted to build a house, you had to make sure that it was phosphate, neutral.
201 00:18:37.235 --> 00:18:44.030 Andrew Clegg, Martock: This was implemented in Somerset, based on 2 assumptions.
202 00:18:44.350 --> 00:18:52.460 Andrew Clegg, Martock: One used the sagis model for modeling where phosphate goes in and out of a system.
203 00:18:53.257 --> 00:19:01.060 Andrew Clotegg, Martock: And this is a desktop model, and they they use statistics in the in defra of
204 00:19:01.150 --> 00:19:18.589 Andrew Clegg, Martock: the number of cattle on a on a in the area. The the food feed that is going in the milk that's coming out, the cheese that's coming out, the amount of urine that's coming out. And so they come up with a model that's that tries to predict
205 00:19:18.620 --> 00:19:41.880 Andrew Clegg, Martock: where the phosphate is coming from and where it is going to. And basically, they said it was about 50 50 sewage works and and agriculture. The problem with models. Desktop models is, as they always say, models are always wrong, but sometimes useful.
206 00:19:42.570 --> 00:19:48.859 Andrew Clegg, Martock: and this one, I think, is particularly wrong, and I'll come to why later.
207 00:19:50.820 --> 00:20:01.429 Andrew Clegg, Martock: Now, the and the second thing the second assumption that was made was that the phosphate is delivered to these Somerset levels and moors through the river Parrett
208 00:20:01.600 --> 00:20:07.460 Andrew Clegg, Martock: and its main tributaries, the tone, the Isle, and the Yeo that
209 00:20:07.830 --> 00:20:13.549 Andrew Clegg, Martock: has not been true for 700 years, but it's still assumed to be true.
210 00:20:15.180 --> 00:20:19.196 Andrew Clegg, Martock: So Somerset introduced a nutrient offsetting program
211 00:20:20.160 --> 00:20:26.410 Andrew Clegg, Martock: which aim to make all its new buildings nutrient neutral throughout their lifetime.
212 00:20:26.890 --> 00:20:33.709 Andrew Clegg, Martock: I don't want to go into the details of that, because it's much more interesting to talk about phosphate rather than local politics.
213 00:20:34.930 --> 00:20:43.520 Andrew Clegg, Martock: But let's let's look at this map. I'm sorry it's a bit blurred. It's actually copied from a document. Here is Somerset.
214 00:20:44.320 --> 00:20:54.549 Andrew Clegg, Martock: Here is the catchment area of the of the main rivers. The river Parrett starts down here and goes up there.
215 00:20:54.760 --> 00:21:00.889 Andrew Clegg, Martock: This is the 1st 2 Ramsar sites as it comes to Martok, is about where the cursor is now
216 00:21:01.430 --> 00:21:06.350 Andrew Clegg, Martock: and then it flows out to the sea in Bridgewater Bay. Up here.
217 00:21:06.620 --> 00:21:10.680 Andrew Clegg, Martock: Now, important thing is that
218 00:21:11.400 --> 00:21:18.139 Andrew Clegg, Martock: West Sedgemore, which is this Ramsar site. Here is 5 metres above sea level.
219 00:21:19.080 --> 00:21:27.930 Andrew Clegg, Martock: Here's sea level. There's a tidal range of 12 meters, there, 10 to 12 meters. So at high tide
220 00:21:28.160 --> 00:21:31.100 Andrew Clegg, Martock: west, Sedgemore is slightly below sea level.
221 00:21:31.490 --> 00:21:42.379 Andrew Clegg, Martock: so here is 30 30 kilometers or so of river that it's got. It's got to go down, and it only goes. It can only go out at high, low tide.
222 00:21:42.730 --> 00:21:48.730 Andrew Clegg, Martock: So that is why that is how the the the, the the
223 00:21:48.890 --> 00:21:52.149 Andrew Clegg, Martock: Somerset levels and Moores started as
224 00:21:52.938 --> 00:21:59.420 Andrew Clegg, Martock: wetlands, because essentially they're all pretty well at sea level.
225 00:22:00.110 --> 00:22:07.840 Andrew Clegg, Martock: Here is is just here is Langport, which is a lovely town in the middle of the levels. Langport
226 00:22:08.110 --> 00:22:21.390 Andrew Clegg, Martock: says it all. It was a port at high tide. You could get quite big ships from Wales up here up the river to Langport. In fact, you could get them as far as as here in in Roman times.
227 00:22:22.000 --> 00:22:29.609 Andrew Clegg, Martock: So it's all very low lying, and at high tide you can move ships up and down here.
228 00:22:32.140 --> 00:22:35.909 tristram cary Winchfield Parish: Sorry, Andrew, can I just just quickly interrupt? Do you get soft water? There.
229 00:22:35.910 --> 00:22:55.400 Andrew Clegg, Martock: No, you don't. It's interesting. I've often wondered about that you don't. The salt water tends to to stop here. What happens is the tide stops or slows down, and then stops the outward flow of the of the of the rivers. You don't get salt water until you're about here.
230 00:22:55.400 --> 00:22:56.170 tristram cary Winchfield Parish: Right.
231 00:22:56.170 --> 00:22:58.519 Andrew Clegg, Martock: So it's sort of brackish up here.
232 00:22:59.756 --> 00:23:02.180 Andrew Clegg, Martock: But then, in the
233 00:23:03.070 --> 00:23:12.310 Andrew Clegg, Martock: in the 13th century, the the monks at Glastonbury decided that this was. This was a silly waste of useful agricultural land.
234 00:23:12.720 --> 00:23:22.559 Andrew Clegg, Martock: and so they decided to to straighten out the River Parrett between 2 levees, that is, about 3 or 4 meters high.
235 00:23:23.060 --> 00:23:25.940 Andrew Clegg, Martock: and then at high tide.
236 00:23:26.200 --> 00:23:51.360 Andrew Clegg, Martock: the river just flowed back up between these 2 levees and didn't flow out into the into the levels, and at low tide they could open up little holes in the side of this to let out the water from the levels and moors back into the river so that it could all get out into the into there. And it's been like that pretty well now since the 13th or 14th century.
237 00:23:52.163 --> 00:23:55.900 Andrew Clegg, Martock: The only difference is that we don't
238 00:23:56.611 --> 00:24:01.890 Andrew Clegg, Martock: open up the sluices in in the sides of the river, although they're still there.
239 00:24:02.600 --> 00:24:11.259 Andrew Clegg, Martock: We pump it out. It's pumped out all all the time. So when too much water comes down from the little hills around the levels.
240 00:24:11.843 --> 00:24:16.509 Andrew Clegg, Martock: it's just pumped into up into the river, and it goes out to sea.
241 00:24:19.490 --> 00:24:21.950 Andrew Clegg, Martock: So so that's where we are now.
242 00:24:22.857 --> 00:24:29.282 Andrew Clegg, Martock: Lots of people have been very concerned about the decline in the state of the levels, and
243 00:24:29.900 --> 00:24:36.920 Andrew Clegg, Martock: everybody. Lots of people around here help with things like dragonfly counts and bird counts, and so on.
244 00:24:37.040 --> 00:24:51.870 Andrew Clegg, Martock: Dragonflies. I have a friend who's been counting dragonflies for 7 for 20 years. 20 years ago he would typically see over a hundred in a couple of hours in the morning. He now typically sees 10. If he's lucky.
245 00:24:52.590 --> 00:24:57.159 Andrew Clegg, Martock: it does vary from day to day. But last year was particularly bad.
246 00:24:59.290 --> 00:25:00.430 Graham Stoddart-Stones - Great Collaboration: Can I ask a question, Andrew?
247 00:25:00.430 --> 00:25:01.390 Andrew Clegg, Martock: Yes.
248 00:25:01.390 --> 00:25:07.319 Graham Stoddart-Stones - Great Collaboration: So when they're pumping the water into the Parrett, does it depend on the state of the tide.
249 00:25:09.365 --> 00:25:26.809 Andrew Clegg, Martock: No. Well, yes and no. And it's a problem in that. When the tide is high and when the rivers are high they tend not to pump any more water into the
250 00:25:26.910 --> 00:25:36.579 Andrew Clegg, Martock: main rivers, and I'll show you a little bit more about that. You know. That's happening as as we speak at the moment. The whole of the levels is one huge lake.
251 00:25:36.710 --> 00:25:42.239 Andrew Clegg, Martock: because they're not pumping out water out into the river, because there's no space in the river.
252 00:25:42.700 --> 00:25:43.380 Graham Stoddart-Stones - Great Collaboration: Alright!
253 00:25:43.380 --> 00:25:51.970 Andrew Clegg, Martock: So we get floods. But we don't get floods from the rivers coming down from here. We get floods from water that's local
254 00:25:52.360 --> 00:25:53.899 Andrew Clegg, Martock: by and large.
255 00:25:54.300 --> 00:25:55.060 Graham Stoddart-Stones - Great Collaboration: 19.
256 00:25:57.090 --> 00:25:59.260 Andrew Clegg, Martock: Well, let's let's go on to.
257 00:26:00.360 --> 00:26:07.519 Andrew Clegg, Martock: This is the main bit of research that I've been doing at the suggestion of English nature. Actually.
258 00:26:08.600 --> 00:26:11.990 Andrew Clegg, Martock: I'm colorblind. This is red, is it?
259 00:26:12.230 --> 00:26:12.990 Graham Stoddart-Stones - Great Collaboration: Yes.
260 00:26:12.990 --> 00:26:14.320 Andrew Clegg, Martock: And that's green.
261 00:26:14.320 --> 00:26:14.950 Graham Stoddart-Stones - Great Collaboration: Yes.
262 00:26:14.950 --> 00:26:15.979 Andrew Clegg, Martock: And that's blue.
263 00:26:16.140 --> 00:26:16.610 Graham Stoddart-Stones - Great Collaboration: Yes.
264 00:26:16.620 --> 00:26:18.450 Andrew Clegg, Martock: Okay, let's look at the blue.
265 00:26:18.870 --> 00:26:30.170 Andrew Clegg, Martock: This is the phosphate concentration during a summer, during a winter, during last summer, during this winter up till yesterday.
266 00:26:30.470 --> 00:26:33.310 Andrew Clegg, Martock: Oh, pretty well, that's normal.
267 00:26:34.000 --> 00:26:46.759 Andrew Clegg, Martock: Phosphate tends to be at a higher concentration in summer, because there's a lot more phosphate going around the phosphate cycle so that there's a general, you know. There's more of it around in the in the water.
268 00:26:47.370 --> 00:26:48.060 Andrew Clegg, Martock: and I'm just.
269 00:26:48.060 --> 00:26:50.730 Cllr Stuart Withington, Gt Dunmow-TC, Essex: That's what the concentration of the phosphate is.
270 00:26:50.930 --> 00:26:59.969 Andrew Clegg, Martock: It's the concentration one is here which phosphate. So this is below one part per 1 million.
271 00:27:00.870 --> 00:27:06.939 Cllr Stuart Withington, Gt Dunmow-TC, Essex: Right. I I just measured one of our rivers and got 200 parts per 1 billion.
272 00:27:07.340 --> 00:27:07.690 Andrew Clegg, Martock: Yeah.
273 00:27:08.040 --> 00:27:09.659 Cllr Stuart Withington, Gt Dunmow-TC, Essex: You're in parts per 1 million. There.
274 00:27:09.660 --> 00:27:16.170 Andrew Clegg, Martock: Yes, important to know exactly what you're measuring. Are you measuring phosphate.
275 00:27:16.410 --> 00:27:19.159 Andrew Clegg, Martock: or are you measuring phosphorus like
276 00:27:19.430 --> 00:27:23.469 Andrew Clegg, Martock: English nature and the environment agency? Do these days.
277 00:27:23.950 --> 00:27:37.960 Andrew Clegg, Martock: If you're if you're if you're like me, a citizen scientist so called, you'll be measuring phosphate because it's done with American instruments. And the Americans measure phosphate. They don't measure phosphorus.
278 00:27:39.365 --> 00:27:39.920 Andrew Clegg, Martock: So.
279 00:27:39.920 --> 00:27:41.199 Cllr Stuart Withington, Gt Dunmow-TC, Essex: And it's lost. Fake.
280 00:27:41.460 --> 00:27:42.890 Andrew Clegg, Martock: Yeah, okay, to get.
281 00:27:42.890 --> 00:27:45.409 Cllr Stuart Withington, Gt Dunmow-TC, Essex: And it's just done with a dipstick.
282 00:27:45.410 --> 00:27:46.670 Andrew Clegg, Martock: Yeah, yeah.
283 00:27:46.800 --> 00:27:56.049 Andrew Clegg, Martock: Yes. Okay, yes, I know. Yes, yeah. And yours is parts per 1 billion. And you'll be doing 200 parts per 1,000,000,300 500 parts per 1 billion, won't you.
284 00:27:56.050 --> 00:27:56.630 Cllr Stuart Withington, Gt Dunmow-TC, Essex: Yes.
285 00:27:56.630 --> 00:28:03.370 Andrew Clegg, Martock: Yeah. Well, this is parts per 1 million. You divide by divide by 3, divided by 3, 3 zeros.
286 00:28:03.530 --> 00:28:04.100 Graham Stoddart-Stones - Great Collaboration: Yeah.
287 00:28:04.100 --> 00:28:10.470 Andrew Clegg, Martock: Knock, knock 3 0. Knock 2 zeros 3 zeros off. Yes, so it's it's less than one
288 00:28:11.923 --> 00:28:18.830 Andrew Clegg, Martock: notice that this is pretty well. It doesn't move much. It just goes roughly up and then down.
289 00:28:19.370 --> 00:28:24.490 Andrew Clegg, Martock: But if we now look at the river flow.
290 00:28:24.720 --> 00:28:33.700 Andrew Clegg, Martock: this is done at the Chiselborough environmental agency station, where they, they measure, river, flow, and they publish it online every 15 min.
291 00:28:34.350 --> 00:28:47.990 Andrew Clegg, Martock: So this is the river flow, and during the winter we get very high flows. This is the up here to more than 10 times normal, in fact, up to up to 50 times normal
292 00:28:48.370 --> 00:28:53.960 Andrew Clegg, Martock: occasionally, and we're quite high at the moment down here.
293 00:28:54.975 --> 00:29:03.859 Andrew Clegg, Martock: Now, this is concentration, which is the amount of phosphate per cubic meter. If you want
294 00:29:03.990 --> 00:29:11.560 Andrew Clegg, Martock: it doesn't tell you the actual amount of phosphate flowing down the river in any given time, like in a day.
295 00:29:11.910 --> 00:29:19.320 Andrew Clegg, Martock: So in order to get the phosphate flow down the river, you multiply the concentration by the river flow.
296 00:29:19.500 --> 00:29:23.619 Andrew Clegg, Martock: and so the amount of phosphate in the river is this one.
297 00:29:24.140 --> 00:29:26.350 Andrew Clegg, Martock: The phosphate flow down the river
298 00:29:26.820 --> 00:29:35.260 Andrew Clegg, Martock: is very low until you get suddenly the river starts flowing, and then you get a much greater amount of phosphate flowing down.
299 00:29:36.550 --> 00:29:39.759 Andrew Clegg, Martock: So the question is, where on earth does that phosphate come from?
300 00:29:40.000 --> 00:29:46.010 Andrew Clegg, Martock: If here you've got what? 4 times as much phosphate as you had a few weeks ago. Where's it coming from?
301 00:29:46.290 --> 00:29:50.700 Graham Stoddart-Stones - Great Collaboration: So that was the question I want. I've been trying to answer.
302 00:29:51.684 --> 00:29:57.200 Andrew Clegg, Martock: I assume that this level here, which is during summer and is pretty constant.
303 00:29:57.480 --> 00:30:00.859 Andrew Clegg, Martock: that comes from the sewage, works upstream.
304 00:30:01.845 --> 00:30:06.710 Andrew Clegg, Martock: We've got 2 major and several minor sewage works feeding the river.
305 00:30:08.345 --> 00:30:10.619 Andrew Clegg, Martock: But then suddenly, in winter
306 00:30:10.760 --> 00:30:12.999 Andrew Clegg, Martock: you get a vast amount of phosphate.
307 00:30:13.240 --> 00:30:19.940 Andrew Clegg, Martock: and in some cases a huge amount of phosphate up there. So the question was, where does it come from?
308 00:30:20.840 --> 00:30:23.690 Andrew Clegg, Martock: I tested some tributaries.
309 00:30:24.570 --> 00:30:31.880 Andrew Clegg, Martock: and they didn't show. The tributaries always showed less phosphate lower concentration of phosphate than the river itself.
310 00:30:32.070 --> 00:30:38.339 Andrew Clegg, Martock: So the phosphate, this amount of missing phosphate wasn't coming from tributaries.
311 00:30:38.820 --> 00:30:44.630 Andrew Clegg, Martock: And the answer is, it's coming from the sediment in the river.
312 00:30:44.790 --> 00:30:50.210 Andrew Clegg, Martock: There's a lot of phosphate tied up with the sediment in the river. When you stir it up
313 00:30:50.810 --> 00:30:53.000 Andrew Clegg, Martock: it releases it into the water.
314 00:30:53.800 --> 00:30:57.649 Andrew Clegg, Martock: and that happens over winter. I've checked all. Yeah.
315 00:30:57.650 --> 00:31:05.349 tristram cary Winchfield Parish: I'm so sorry I've got I'm lost. Can you just explain something to me? Is that is that green line the flow
316 00:31:05.600 --> 00:31:09.059 tristram cary Winchfield Parish: in parts per 1 million still? Or is it in.
317 00:31:09.060 --> 00:31:09.470 Andrew Clegg, Martock: You know that.
318 00:31:09.470 --> 00:31:10.370 tristram cary Winchfield Parish: Unit.
319 00:31:10.370 --> 00:31:19.269 Andrew Clegg, Martock: This is phosphate amount, and it's in on this scale, and this is in kilograms per hour.
320 00:31:19.440 --> 00:31:23.040 Andrew Clegg, Martock: So the amount flowing past in kilograms per hour.
321 00:31:24.990 --> 00:31:26.390 Andrew Clegg, Martock: So up here.
322 00:31:26.390 --> 00:31:28.009 tristram cary Winchfield Parish: River flue. That's a river flue in Kilogra.
323 00:31:28.010 --> 00:31:31.119 Andrew Clegg, Martock: This is the river flow. This is the river flow in
324 00:31:31.340 --> 00:31:35.359 Andrew Clegg, Martock: meters per second. Cubic meters per second.
325 00:31:35.360 --> 00:31:35.970 tristram cary Winchfield Parish: Yes.
326 00:31:36.210 --> 00:31:39.800 Andrew Clegg, Martock: This is the phosphate flow in kilograms per hour.
327 00:31:39.970 --> 00:31:45.600 tristram cary Winchfield Parish: Oh, kilograms per hour! It's unrelated, it's unrelated. Then, to the concentration.
328 00:31:45.600 --> 00:31:49.340 Andrew Clegg, Martock: Well, it is related to. It's it. That's the odd thing, isn't it?
329 00:31:49.340 --> 00:31:49.680 tristram cary Winchfield Parish: Yeah.
330 00:31:49.680 --> 00:32:05.989 Andrew Clegg, Martock: It seems to be pretty well unrelated, I mean, that's a little bit related. Do you see? There it goes up a little bit here, but it goes up very huge. So this is the odd thing that struck me when I 1st found it as odd. But it didn't strike
331 00:32:06.120 --> 00:32:11.269 Andrew Clegg, Martock: the scientists at Lancaster University is odd. They said, Yeah, it's just what you expect.
332 00:32:11.990 --> 00:32:14.130 Andrew Clegg, Martock: You you you.
333 00:32:14.420 --> 00:32:26.039 Andrew Clegg, Martock: If you put a lot of water down the river, it stirs the river up. It stirs the sediment up, and it looks like almost like milk down here because of the clay. It gets very turbid.
334 00:32:26.210 --> 00:32:33.879 Andrew Clegg, Martock: and what you're doing is you're releasing a lot of phosphate from the from the sediment to the river.
335 00:32:34.250 --> 00:32:46.440 Andrew Clegg, Martock: And this phosphate in the sediment has built up over years from the sewage works. In fact, Lancaster, tell me it's been building up for a century
336 00:32:46.820 --> 00:32:50.449 Andrew Clegg, Martock: in most rivers and in fields.
337 00:32:50.680 --> 00:32:56.610 Andrew Clegg, Martock: So we're getting we're getting a gradual build up of phosphate over time
338 00:32:57.060 --> 00:33:01.359 Andrew Clegg, Martock: accelerated greatly in the last 30, 40 years.
339 00:33:01.970 --> 00:33:08.839 Andrew Clegg, Martock: And they are particularly concerned about this, because it's not only in the Riverbank sediment. It's in the soil everywhere.
340 00:33:10.750 --> 00:33:11.530 Andrew Clegg, Martock: So
341 00:33:13.640 --> 00:33:24.490 Andrew Clegg, Martock: I can't think if there's anything in my more I want to say about this, except that it's it's I've got a colleague now doing the same
342 00:33:24.760 --> 00:33:31.890 Andrew Clegg, Martock: kind of graph further downstream in Langport, where they've just opened a new environmental agency station.
343 00:33:33.280 --> 00:33:43.279 Andrew Clegg, Martock: But it's useful is that it gives us, I think, a good picture of actually what's happening in the river. What we're now looking for, of course.
344 00:33:43.480 --> 00:33:48.929 Andrew Clegg, Martock: is that the Wessex water over the last 3 or 4 months
345 00:33:49.220 --> 00:33:54.749 Andrew Clegg, Martock: have stopped the phosphate pretty well coming out of
346 00:33:54.960 --> 00:33:58.810 Andrew Clegg, Martock: 3 of the sewage works in.
347 00:33:58.950 --> 00:34:07.700 Andrew Clegg, Martock: and the Parrett, and what we're hoping to see is that gradually this level is going to get less and less.
348 00:34:08.080 --> 00:34:17.260 Andrew Clegg, Martock: But the thing is, how long will it take to get down to almost 0. Will it be a year or 2, or will it be a century?
349 00:34:18.190 --> 00:34:27.970 Andrew Clegg, Martock: Much depends on how much phosphate is there is hanging around in the sediment, I suspect. So this is going to be quite an interesting investigation.
350 00:34:28.179 --> 00:34:32.469 Graham Stoddart-Stones - Great Collaboration: Andrew, what's a desirable level of phosphate concentration.
351 00:34:32.730 --> 00:34:34.759 Andrew Clegg, Martock: About a 10th of this.
352 00:34:34.760 --> 00:34:35.550 Graham Stoddart-Stones - Great Collaboration: Wow!
353 00:34:35.550 --> 00:34:36.030 tristram cary Winchfield Parish: Well.
354 00:34:36.030 --> 00:34:37.210 Graham Stoddart-Stones - Great Collaboration: No point, one.
355 00:34:37.219 --> 00:34:39.299 Andrew Clegg, Martock: Yeah, no, not 0 point 1.
356 00:34:39.639 --> 00:34:42.429 tristram cary Winchfield Parish: And is it easy to remove the phosphate from the sediment?
357 00:34:42.560 --> 00:34:44.709 tristram cary Winchfield Parish: Can you filter the sediment.
358 00:34:44.850 --> 00:34:52.430 Andrew Clegg, Martock: No, it's very firmly bound. It's insoluble pretty well most of the time, but it if you.
359 00:34:52.530 --> 00:35:06.300 Andrew Clegg, Martock: if you put a lot of fresh water into the into the river. Then some of that bound phosphate will come out into the and be soluble phosphate in the river.
360 00:35:07.370 --> 00:35:11.910 Andrew Clegg, Martock: You know this is just in. This is very, very, so very little
361 00:35:12.460 --> 00:35:29.410 Andrew Clegg, Martock: phosphate even up here you'd in in a liter of this river water to get that concentration. You've just got a it's a bit like a like a sugar crystals worth. It's very, very insoluble.
362 00:35:29.690 --> 00:35:30.390 Graham Stoddart-Stones - Great Collaboration: Move.
363 00:35:31.190 --> 00:35:38.779 tristram cary Winchfield Parish: So I'm not. Maybe I'm not understanding. But if you said that when the flow is high, then the phosphate comes out of the sediment. So you've got.
364 00:35:38.780 --> 00:35:39.350 Andrew Clegg, Martock: Yes, he does.
365 00:35:39.350 --> 00:35:42.460 tristram cary Winchfield Parish: Whether it's soluble or not. So I was wondering.
366 00:35:42.680 --> 00:35:50.559 tristram cary Winchfield Parish: I was wondering if it's possible to dig up the sediment in a patch. Say, and put it in a bucket, and somehow filter out the fossage.
367 00:35:50.560 --> 00:36:03.030 Andrew Clegg, Martock: No, the answer is, no, it's interesting that this is. It's a thing called a chemical equilibrium. I won't bore you with that, Tristram, but I can send you some references, some reading references, if you like.
368 00:36:03.030 --> 00:36:03.850 tristram cary Winchfield Parish: Basic.
369 00:36:03.850 --> 00:36:20.450 Andrew Clegg, Martock: It's not, it's not within our control. It is a natural equilibrium between the concentration of the phosphate in the sediment and the concentration of phosphate in the water, which tends to remain a constant ratio, no matter what you do.
370 00:36:21.400 --> 00:36:26.050 tristram cary Winchfield Parish: So it's a it's an it's a it's a chemical equilibrium between the 2.
371 00:36:26.380 --> 00:36:28.810 Graham Stoddart-Stones - Great Collaboration: Andrew, what does this do to the sea, where all the slot is a.
372 00:36:29.262 --> 00:36:37.909 Andrew Clegg, Martock: I was hoping you weren't going to ask me that question, Graham, so I'm going to ignore it. I.
373 00:36:37.910 --> 00:36:39.210 Graham Stoddart-Stones - Great Collaboration: Politician, you.
374 00:36:39.210 --> 00:36:55.569 Andrew Clegg, Martock: I have no idea, but I suspect that this is part of the wider phosphate cycle that it will. It will go into sediment in the sea, and over long periods of time that'll be in phosphate rock, and and so on.
375 00:36:55.980 --> 00:36:59.009 Andrew Clegg, Martock: I just don't know that half of it at all.
376 00:37:00.480 --> 00:37:03.820 Cllr Stuart Withington, Gt Dunmow-TC, Essex: Would it be worth measuring the turbidity.
377 00:37:04.360 --> 00:37:08.589 Andrew Clegg, Martock: I do measure the turbidity. Yes, it is worth it.
378 00:37:10.465 --> 00:37:15.489 Cllr Stuart Withington, Gt Dunmow-TC, Essex: By pairing the turbidity and the amount of phosphate
379 00:37:15.942 --> 00:37:20.939 Cllr Stuart Withington, Gt Dunmow-TC, Essex: you should be able to tell, because I presume you're you're gradually washing out the phosphate.
380 00:37:20.940 --> 00:37:23.020 Andrew Clegg, Martock: Yeah, yes, you are.
381 00:37:23.020 --> 00:37:26.350 Cllr Stuart Withington, Gt Dunmow-TC, Essex: Compared to ability, which probably won't change
382 00:37:26.580 --> 00:37:32.139 Cllr Stuart Withington, Gt Dunmow-TC, Essex: with the level of phosphate. Then you should see that going down.
383 00:37:32.150 --> 00:37:44.610 Andrew Clegg, Martock: No, actually, the turbidity does change. It's it's turbid on these times, and it's it's actually off the scale of my turbidity meter.
384 00:37:44.870 --> 00:37:50.999 Andrew Clegg, Martock: But it very quickly settles down, and the Parrett water is beautifully clear most of the time.
385 00:37:52.417 --> 00:37:58.269 Andrew Clegg, Martock: And so it it's you know you you can't get much
386 00:37:59.360 --> 00:38:13.530 Andrew Clegg, Martock: phosphate out by somehow removing the the sediment it would be very difficult to remove, anyway, because it's very, very fine. It's like milk. It's like milk. Almost you can't really filter it. It blocks up all the filters, as Wessex water knows.
387 00:38:14.330 --> 00:38:23.120 Graham Stoddart-Stones - Great Collaboration: Just out of interest. Does anyone measure the phosphate upstream from, say, the Severn bore? Because is that carrying phosphate that is picked up from the Bristol Channel.
388 00:38:23.470 --> 00:38:30.779 Andrew Clegg, Martock: I don't know. It requires people like me to do this because the environment agency can't afford to do it anymore.
389 00:38:31.470 --> 00:38:33.959 Andrew Clegg, Martock: You see, they used to do it until 2,018.
390 00:38:34.260 --> 00:38:35.910 Andrew Clegg, Martock: They used to do it once a month.
391 00:38:36.190 --> 00:38:47.639 Andrew Clegg, Martock: But in order to do this, to get a decent set of results that you you can use. You have to do it daily, or even every 15 min.
392 00:38:47.820 --> 00:38:49.959 Graham Stoddart-Stones - Great Collaboration: We depend upon the citizen scientists.
393 00:38:49.960 --> 00:38:54.879 Graham Stoddart-Stones - Great Collaboration: Yeah. And this, this process that I'm using is difficult to automate.
394 00:38:56.057 --> 00:38:58.859 Andrew Clegg, Martock: You know. So it requires people.
395 00:39:02.030 --> 00:39:09.120 Andrew Clegg, Martock: let's go on a little bit. Here's the Parrett. This is where I measure it. This is upstream looking upstream. That's all the Parrett is.
396 00:39:09.300 --> 00:39:19.120 Andrew Clegg, Martock: It's less than one cubic meter per second flowing out of this under here I'm standing on the bridge parapet to take this photograph.
397 00:39:19.270 --> 00:39:21.040 Andrew Clegg, Martock: That's normal level.
398 00:39:22.826 --> 00:39:27.320 Andrew Clegg, Martock: Basically. This. The summer load
399 00:39:28.130 --> 00:39:36.780 Andrew Clegg, Martock: is about 40 kg a day, as I mentioned, and it's due to sewage plants. There's very little coming in from agriculture. That's the assumption.
400 00:39:36.780 --> 00:39:41.020 Graham Stoddart-Stones - Great Collaboration: But that's changed now because of Wessex waters, updates or improve.
401 00:39:41.020 --> 00:39:57.730 Andrew Clegg, Martock: And that well, we're looking. It's gone down to 32 at the last time I I did it when when it was a low flow. But we've had. We've had very high flows over the for most of the time over the last month, you see, so I haven't had much of an opportunity.
402 00:39:58.900 --> 00:40:05.689 Andrew Clegg, Martock: This is an interesting one that's going to. We're going to follow. And Wessex water is particularly interested in what's going to happen to this each day.
403 00:40:06.920 --> 00:40:10.790 Andrew Clegg, Martock: Another thing is that If
404 00:40:11.150 --> 00:40:17.900 Andrew Clegg, Martock: farmers obey the rules for farming near water, and most of the farmers do around us.
405 00:40:18.890 --> 00:40:24.120 Andrew Clegg, Martock: then you don't see phosphate in the little tributaries.
406 00:40:24.600 --> 00:40:37.240 Andrew Clegg, Martock: I've sampled several of the. They're very deep reams, and there's a little a little bit of water at the bottom. Whenever I sample that little bit of water I seldom find phosphate.
407 00:40:39.480 --> 00:40:44.180 Andrew Clegg, Martock: Basically phosphate as soon as it goes into the clay. Here
408 00:40:44.760 --> 00:40:53.719 Andrew Clegg, Martock: in the top 2 or 3 inches it removes the phosphate. So anything that's coming out into the Renes and into the river is pretty clean.
409 00:40:53.720 --> 00:40:55.710 tristram cary Winchfield Parish: Sorry what removes the phosphate.
410 00:40:55.710 --> 00:41:01.550 Andrew Clegg, Martock: The soil, the soil, the aluminium in the clay, the aluminium and iron
411 00:41:01.750 --> 00:41:07.669 Andrew Clegg, Martock: removes phosphate very quickly. I think most of it is removed in the top 2 or 3 inches.
412 00:41:08.100 --> 00:41:20.509 Andrew Clegg, Martock: but the land drains that the farmers put in around here are usually about 50 cm down, and whenever I've tested the output of a land drain. I haven't found any phosphate at all.
413 00:41:20.630 --> 00:41:24.499 tristram cary Winchfield Parish: When you say removed, you mean it's reacted with into something.
414 00:41:24.500 --> 00:41:27.940 Andrew Clegg, Martock: Combined with it's combined with
415 00:41:28.270 --> 00:41:42.579 Andrew Clegg, Martock: aluminium in the, in the, in the soil, and and you get aluminium, phosphate, or crystals, which contain aluminium, phosphate soils which contain aluminium, phosphate, and and the phosphate stays there.
416 00:41:42.730 --> 00:41:46.519 tristram cary Winchfield Parish: And but it doesn't matter. If that gets in the water it doesn't matter. It's not phosphate anymore.
417 00:41:46.520 --> 00:41:48.339 Andrew Clegg, Martock: It doesn't get into the river.
418 00:41:48.720 --> 00:41:52.760 Andrew Clegg, Martock: But I'll come to a little bit more in a moment, Tristram, about where it does go.
419 00:41:52.760 --> 00:41:53.319 tristram cary Winchfield Parish: Thank you.
420 00:41:54.016 --> 00:42:00.859 Andrew Clegg, Martock: So defra rules work well, most farmers around here obey the Defra rules.
421 00:42:01.450 --> 00:42:09.589 Andrew Clegg, Martock: A few don't and since we started taking this started doing this work.
422 00:42:10.260 --> 00:42:17.529 Andrew Clegg, Martock: The environment Agency has been able to use what we've been doing to successfully prosecute 2 farmers.
423 00:42:18.060 --> 00:42:18.630 Graham Stoddart-Stones - Great Collaboration: Right.
424 00:42:18.630 --> 00:42:20.479 Andrew Clegg, Martock: We haven't given them the.
425 00:42:20.790 --> 00:42:29.289 Andrew Clegg, Martock: We haven't given them details. We've just told them what we're doing. And we think there's pointing out where there's a problem they know
426 00:42:29.470 --> 00:42:38.279 Andrew Clegg, Martock: as soon as I, you know you give them a reference. They know which farm to go and visit, and so they go and visit. The trouble is.
427 00:42:38.650 --> 00:42:41.280 Andrew Clegg, Martock: but they don't prosecute them for pollution.
428 00:42:41.520 --> 00:42:45.980 Andrew Clegg, Martock: They prosecute, they tell them what they have to do to stop the pollution.
429 00:42:46.480 --> 00:43:06.850 Andrew Clegg, Martock: and then they go on an unannounced visit to the farm a few weeks later, and if they haven't done it, it's quite easy to prosecute. But you don't prosecute for pollution you prosecute for disobeying the environment agency. And so you don't find them 100,000. You find them for 10,000,
430 00:43:07.560 --> 00:43:13.880 Andrew Clegg, Martock: and that's probably a quite cheap way of disposings of slurry
431 00:43:14.370 --> 00:43:21.670 Andrew Clegg, Martock: being fined 10,000 pounds per 5 years or so, if you've got 3,000 cows.
432 00:43:22.930 --> 00:43:26.509 Andrew Clegg, Martock: so some of these farmers are now prosecuted regularly.
433 00:43:28.270 --> 00:43:38.719 Andrew Clegg, Martock: but there are very few of them, and it's a bit embarrassing for the ones that are, you know, that are do do value that what they're doing and what value the land?
434 00:43:45.270 --> 00:43:47.230 Andrew Clegg, Martock: I took this photograph last night.
435 00:43:47.890 --> 00:43:52.094 Andrew Clegg, Martock: It's a pond, and ponds are usually very
436 00:43:52.740 --> 00:44:08.479 Andrew Clegg, Martock: phosphate free. This is a flood alleviation pond very close to us. It's actually part of a little nature reserve which we're developing. The land belongs to highways, England or national highways. I think it's called now.
437 00:44:08.640 --> 00:44:13.359 Andrew Clegg, Martock: and we've taken it over and run it for them as a little nature reserve.
438 00:44:13.780 --> 00:44:17.399 Andrew Clegg, Martock: And this this pond, even though it's fed
439 00:44:17.890 --> 00:44:22.679 Andrew Clegg, Martock: from a fairly phosphate rich streams.
440 00:44:23.506 --> 00:44:36.300 Andrew Clegg, Martock: After a couple of days of flowing into here, there's very little sign of phosphate. So one useful way of removing phosphate is good quality, flood alleviation schemes.
441 00:44:38.540 --> 00:44:40.610 Andrew Clegg, Martock: Another picture here.
442 00:44:42.640 --> 00:44:46.190 Andrew Clegg, Martock: This is taken last week.
443 00:44:47.690 --> 00:44:53.840 Andrew Clegg, Martock: and this is the river Parrett flowing down here down here to Langport.
444 00:44:54.240 --> 00:44:57.860 Andrew Clegg, Martock: This is from the bridge at a place called Matzulny.
445 00:44:58.330 --> 00:45:08.519 Andrew Clegg, Martock: which is a place that gets flooded regularly, and in the last floods the big floods of 2,013, it was visited by David Cameron
446 00:45:08.670 --> 00:45:14.620 Andrew Clegg, Martock: in A, in a brand new pair of clean green wellies, everybody noticed.
447 00:45:14.740 --> 00:45:21.899 Andrew Clegg, Martock: and then it was visited again about a week later by Prince Charles in a very dirty pair of green wellies.
448 00:45:23.197 --> 00:45:28.659 Andrew Clegg, Martock: But the point about this is that this is in this is, it looks as though it's in flood.
449 00:45:29.460 --> 00:45:36.659 Andrew Clegg, Martock: In fact, it's maintained at this high level. Artificially, this is the flooding area.
450 00:45:36.830 --> 00:46:03.350 Andrew Clegg, Martock: This is in flood, and this water has a much higher concentration of phosphate than this water, probably twice as much. The reason is that this is the local water. The flood is running over the local fields. It's picking up phosphate from the fields which has been put in there for a hundred years. So in your top few inches of field. You've got quite a lot of phosphate.
451 00:46:03.630 --> 00:46:12.100 Andrew Clegg, Martock: And so that picks up quite a lot from there. So this phosphate concentration is double that phosphate concentration.
452 00:46:13.207 --> 00:46:23.280 Andrew Clegg, Martock: It looks like if if you look at the levels at the moment and look down on it, it looks like one mass of water everywhere.
453 00:46:23.450 --> 00:46:31.149 Andrew Clegg, Martock: But in fact, it's different bits of water that are pretty well independent of each other.
454 00:46:31.865 --> 00:46:40.610 Andrew Clegg, Martock: As far as possible, and that's manipulated by the environment agency operating the sluices very cleverly, I think.
455 00:46:43.950 --> 00:46:45.400 Andrew Clegg, Martock: So these are the.
456 00:46:45.750 --> 00:46:51.400 Andrew Clegg, Martock: These are the 2 issues here, the additional phosphate due to legacy, phosphate in river sediments
457 00:46:51.670 --> 00:46:59.280 Andrew Clegg, Martock: and a lot of that phosphate washed out of the soil goes into here. Question is what happens to this
458 00:47:00.600 --> 00:47:04.490 Andrew Clegg, Martock: when it is pumped out?
459 00:47:05.010 --> 00:47:08.040 Andrew Clegg, Martock: And that's an interesting research question.
460 00:47:08.910 --> 00:47:11.809 Andrew Clegg, Martock: does flooding of the levels
461 00:47:12.480 --> 00:47:18.340 Andrew Clegg, Martock: reduce the concentration of the phosphate in the Somerset levels? Or does it increase it?
462 00:47:19.293 --> 00:47:28.179 Andrew Clegg, Martock: At the moment my feeling is that it reduces it, that a lot of this will go out when it's pumped out.
463 00:47:28.460 --> 00:47:31.530 Andrew Clegg, Martock: and that will take a lot of phosphate away.
464 00:47:33.360 --> 00:47:41.810 Andrew Clegg, Martock: But how long that will take to substantially reduce the amount of phosphate around in the levels nobody really knows.
465 00:47:44.575 --> 00:47:45.059 Andrew Clegg, Martock: I.
466 00:47:45.060 --> 00:47:46.480 tristram cary Winchfield Parish: Andrew, can I ask question?
467 00:47:46.480 --> 00:47:47.040 Andrew Clegg, Martock: Yeah.
468 00:47:47.040 --> 00:47:52.270 tristram cary Winchfield Parish: That water to the right is you're you're saying, is the flood.
469 00:47:52.270 --> 00:47:52.810 Andrew Clegg, Martock: Yeah.
470 00:47:52.810 --> 00:48:00.010 tristram cary Winchfield Parish: Prevention. So doesn't that act like a pond? And you said in a few slides before that, then in a pond, the phosphate settles out.
471 00:48:00.470 --> 00:48:04.529 Andrew Clegg, Martock: Yeah, that's that's that's a question that I'm stud trying to study
472 00:48:05.160 --> 00:48:29.559 Andrew Clegg, Martock: when it when it comes out. When that that water accumulates, because there's a pump. There's a pump down here, and they've stopped pumping it out. You see, as it accumulates, it takes phosphate from the from the top layer of the grassland there that turns out to be pretty high
473 00:48:29.810 --> 00:48:31.110 Andrew Clegg, Martock: now, as it
474 00:48:31.580 --> 00:48:41.139 Andrew Clegg, Martock: as it drains away, either naturally or artificially. What we find is that the phosphate that's left
475 00:48:41.350 --> 00:48:46.080 Andrew Clegg, Martock: in the drainage channels within this area is much lower.
476 00:48:46.910 --> 00:48:53.189 Andrew Clegg, Martock: and, in fact, almost in this particular one, which is called Wetmoor. When I test the wet moor.
477 00:48:53.510 --> 00:48:59.059 Andrew Clegg, Martock: Renes, just after the phosphate, is that this floods have gone.
478 00:48:59.400 --> 00:49:01.610 Andrew Clegg, Martock: I find very little in the Renes.
479 00:49:02.620 --> 00:49:06.650 Andrew Clegg, Martock: Not quite sure why I should find very little in the Renes, but I do
480 00:49:07.570 --> 00:49:16.210 Andrew Clegg, Martock: so. There's a there's. There are issues here which seem to me certainly not clear at the moment.
481 00:49:16.910 --> 00:49:22.145 Andrew Clegg, Martock: And and you know the the I'm not the only person that's that's
482 00:49:23.180 --> 00:49:26.609 tristram cary Winchfield Parish: You said on the ponds that the ponds, when they've
483 00:49:27.030 --> 00:49:31.570 tristram cary Winchfield Parish: have new water put in very high phosphates, and then, after a day or 2, it's all clear.
484 00:49:31.660 --> 00:49:40.629 Andrew Clegg, Martock: Well that you see, the pond is the pond is a permanent thing. This is a flood water, and it will go down. It'll soak in the pond stays there.
485 00:49:40.840 --> 00:49:57.029 Andrew Clegg, Martock: and the phosphate in the pond is taken up by the weed that's growing around the edges, and the weed that's growing in the pond, and so on. That's oxygenating the pond and everything. So if you've got a healthy pond.
486 00:49:57.310 --> 00:49:58.549 Andrew Clegg, Martock: then it removes phosphate.
487 00:49:58.940 --> 00:50:01.430 tristram cary Winchfield Parish: Isn't a pond. This is a flood.
488 00:50:04.643 --> 00:50:05.970 Andrew Clegg, Martock: Last one.
489 00:50:07.450 --> 00:50:14.559 Andrew Clegg, Martock: Well, there's a few research questions. I'm going to ignore those for a moment, because I like this photograph
490 00:50:15.180 --> 00:50:19.470 Andrew Clegg, Martock: just behind me up in in the
491 00:50:19.570 --> 00:50:28.690 Andrew Clegg, Martock: the hills at where we've got a hill fort behind me, and behind that we've got a Mott and Bailey Castle
492 00:50:28.960 --> 00:50:41.590 Andrew Clegg, Martock: that was dates from the 11th century, isn't it? About 1070, 1060, something. And at the top of the Motton Bailey Castle this is the view down the river Parrett
493 00:50:41.940 --> 00:50:49.490 Andrew Clegg, Martock: all the way to the sea, and the sea is just down there, and on a really good day
494 00:50:49.710 --> 00:50:54.900 Andrew Clegg, Martock: with a pair of binoculars. You can see big Carl.
495 00:50:55.060 --> 00:50:57.849 Andrew Clegg, Martock: Do you know who Big Carl is?
496 00:50:59.000 --> 00:51:18.329 Andrew Clegg, Martock: It's the biggest mobile crane in the world. It can lift 5,000 tons a radius around a radius of 40 meters, and it can lift it up as high as 250 meters. A quarter of a kilometer.
497 00:51:18.330 --> 00:51:19.960 Cllr Stuart Withington, Gt Dunmow-TC, Essex: Building size, we'll see.
498 00:51:19.960 --> 00:51:22.809 Graham Stoddart-Stones - Great Collaboration: And it's building size. We'll see.
499 00:51:22.810 --> 00:51:23.720 Graham Stoddart-Stones - Great Collaboration: Please see.
500 00:51:23.940 --> 00:51:24.510 Andrew Clegg, Martock: That's.
501 00:51:24.510 --> 00:51:25.690 Cllr Stuart Withington, Gt Dunmow-TC, Essex: Hang. Please. Sorry.
502 00:51:25.690 --> 00:51:41.619 Andrew Clegg, Martock: See? Yeah. And you can see this huge crane and a few others around about it, through binoculars. 30 odd kilometers away from the top of our little Martin Bailey Castle. But here are a list of a few
503 00:51:42.180 --> 00:51:47.380 Andrew Clegg, Martock: research questions that have been occurring to both me and other people who are looking into this
504 00:51:48.620 --> 00:51:50.279 Andrew Clegg, Martock: about what.
505 00:51:51.020 --> 00:51:59.139 Andrew Clegg, Martock: how we should sort the the the levels problem out. My feeling is that the key thing is this one
506 00:52:00.570 --> 00:52:06.590 Andrew Clegg, Martock: is it is the the problem, the levels problem, a phosphate problem.
507 00:52:06.800 --> 00:52:08.970 Andrew Clegg, Martock: Or is it a global warming problem?
508 00:52:09.570 --> 00:52:16.930 Andrew Clegg, Martock: And my feeling is that after working on this for 2 years. I'm pretty sure that this is a global warming problem.
509 00:52:17.400 --> 00:52:26.400 Andrew Clegg, Martock: and the phosphate is just an exacerbating effect which makes it a bit worse and a really bad year.
510 00:52:26.790 --> 00:52:32.679 Andrew Clegg, Martock: because we've had. We've just had a year where we've had rain pretty well through the summer.
511 00:52:33.180 --> 00:52:51.999 Andrew Clegg, Martock: and we haven't had the same problem in the Renes in the levels as we had the previous year when we had the drought. So my feeling is that we're not looking at a simple, relatively simple phosphate issue. We're looking at a much more serious and complex issue which is global warming.
512 00:52:53.730 --> 00:52:58.920 Andrew Clegg, Martock: And I don't know how you help out the Somerset levels
513 00:52:59.848 --> 00:53:01.940 Andrew Clegg, Martock: out of out of that.
514 00:53:02.784 --> 00:53:09.479 Andrew Clegg, Martock: But we're trying to think of things like polluti culture. What can you grow in the Somerset levels which will
515 00:53:09.620 --> 00:53:15.260 Andrew Clegg, Martock: remove phosphate better than the cattle that are there growing at the moment.
516 00:53:16.970 --> 00:53:23.730 Andrew Clegg, Martock: One thing that we're investigating is or that is being investigated is growing willow with ease.
517 00:53:24.010 --> 00:53:29.909 Andrew Clegg, Martock: Traditional crop in the Somerset levels. It's now coming back into fashion and
518 00:53:30.180 --> 00:53:47.450 Andrew Clegg, Martock: into use. And you I can. You can either make attractive things out of it. It can be a high end, economic crop, or you or you or you can chip it and burn it in power stations.
519 00:53:48.880 --> 00:53:57.590 Andrew Clegg, Martock: So things are happening. People, things are having. Ideas are coming forward and being tested. But we're in early stages.
520 00:53:59.250 --> 00:54:03.790 Andrew Clegg, Martock: Okay, that's pretty well everything.
521 00:54:03.960 --> 00:54:04.860 Andrew Clegg, Martock: M.
522 00:54:05.400 --> 00:54:08.450 Andrew Clegg, Martock: Any questions. Shall I shall I switch?
523 00:54:09.380 --> 00:54:13.600 Andrew Clegg, Martock: Shall I share? Pass the screen over? Graham.
524 00:54:13.600 --> 00:54:20.969 Graham Stoddart-Stones - Great Collaboration: No, by all means. But, Andrew, thank you so much. I found that utterly fascinating. It was a really very interesting
525 00:54:22.640 --> 00:54:26.660 Graham Stoddart-Stones - Great Collaboration: presentation, largely because it upsets pre-considered. You know
526 00:54:27.110 --> 00:54:56.099 Graham Stoddart-Stones - Great Collaboration: I do have a question, though there's reverting to your the difference between a pond and a lake in terms of how much cleaning it can do, since all of those fields are covered in grass, and the grass continues to thrive underwater, because when the water disappears it's very much alive, is it not removing some of the phosphate? And that sort of leads to a second question, which is those high levels of phosphate in the soil do they assist in the growth of what the crops are in the field?
527 00:54:56.520 --> 00:55:10.770 Andrew Clegg, Martock: I think the answer to the second one is certainly yes, but how much phosphate, you know it's it's a good nutrient, and then, of course they will harvest it as a hay crop.
528 00:55:11.050 --> 00:55:25.350 Andrew Clegg, Martock: Not a particularly good hay crop, because these days, because it's not the high yielding ryegrass that is now grown for hay, but the farmers do harvest it, and there are farmers on the levels.
529 00:55:26.030 --> 00:55:49.180 Andrew Clegg, Martock: and an increasing number now, I think, who who are working at that sort of high value end of of livestock, rearing with particular, you know, with belted Galloway cattle, and so on, and and making cheeses and things like that at sort of at the high end, and that seems to be a sustainable
530 00:55:51.550 --> 00:56:02.659 Andrew Clegg, Martock: farming, whereas the around West Sedgemore there are several dairies, each of which with several 1,000 head of cattle.
531 00:56:02.900 --> 00:56:05.729 Andrew Clegg, Martock: and they have an awful lot of slurry to get rid of.
532 00:56:06.300 --> 00:56:15.890 Andrew Clegg, Martock: and that is creating the problem, particularly in a year like this, because they have to get rid of their slurry in the next 2 days.
533 00:56:16.070 --> 00:56:23.539 Andrew Clegg, Martock: because at the end of February the season for spreading slurry. Liquid slurry is is at an end.
534 00:56:23.840 --> 00:56:31.669 Andrew Clegg, Martock: and you can't spread liquid slurry on saturated clay. You're not allowed to do it. So it's a it's a serious problem.
535 00:56:34.100 --> 00:56:35.220 Graham Stoddart-Stones - Great Collaboration: And is it
536 00:56:35.767 --> 00:56:42.750 Graham Stoddart-Stones - Great Collaboration: does the phosphorus go into, or the phosphate go into the food chain through the cows and the cheese, and so forth?
537 00:56:43.770 --> 00:56:46.889 Andrew Clegg, Martock: Yes. The the question is, where does it?
538 00:56:47.030 --> 00:57:00.379 Andrew Clegg, Martock: You know whether it goes outside the levels or not? What is happening at the moment is that or outside the level levels catchment, the the bigger the bigger the larger area.
539 00:57:00.590 --> 00:57:09.180 Andrew Clegg, Martock: And what's happening now is that an increasing number of fields. Increasing acreage is being put over to maize.
540 00:57:09.390 --> 00:57:12.700 Andrew Clegg, Martock: and that is being fed by the
541 00:57:12.800 --> 00:57:19.289 Andrew Clegg, Martock: by the solids left at this and the slurry pit in the more distant fields from the farm.
542 00:57:19.850 --> 00:57:29.040 Andrew Clegg, Martock: or by slurry applied between between October and February and the fields that are near these large farms.
543 00:57:29.430 --> 00:57:48.789 Andrew Clegg, Martock: Again, if these farms you know. Technically they should be phosphate, neutral, and they do advertise themselves as phosphate neutral, because the phosphate that the cattle make, which is all in the collected in barns is put on the fields, which then is converted into maize.
544 00:57:49.220 --> 00:58:00.850 Andrew Clegg, Martock: The problem is, what happens with accidents, or if you've, you know, or if you're not if you don't obey the the farming, for for water rules that defer have laid down.
545 00:58:02.830 --> 00:58:10.909 Graham Stoddart-Stones - Great Collaboration: Utterly fascinating, very intriguing, and anybody else got any questions.
546 00:58:10.910 --> 00:58:27.429 tristram cary Winchfield Parish: Yeah, I just wanted to again, just to clarify my understanding. You said that the sewage works are now much better at filtering out the phosphates before they get into the watercourse. So if the farmers in general are obeying the rules, and that's not what the problem is.
547 00:58:27.610 --> 00:58:36.589 tristram cary Winchfield Parish: isn't isn't. Haven't we solved the problem just by making the sewage treatment much more effective at getting rid of the phosphate at that stage.
548 00:58:36.940 --> 00:58:55.109 Andrew Clegg, Martock: Hopefully. That's why that's why people are taking notice of the results that I'm taking now. Because Wessex Water are very interested in this. They measure the phosphate that's that's coming out of their sewage works. And that's very little now, and I've measured that as well, and it's very little.
549 00:58:55.270 --> 00:58:59.839 Andrew Clegg, Martock: But by 50 to a hundred meters downstream.
550 00:59:00.240 --> 00:59:12.960 Andrew Clegg, Martock: There's I can detect very little change, because, of course, the cleaner water that's coming out of the sewage works is quickly, taking up phosphate from the from the river banks and the sediment.
551 00:59:13.280 --> 00:59:16.009 Andrew Clegg, Martock: And we're back to normal.
552 00:59:16.010 --> 00:59:17.539 tristram cary Winchfield Parish: Will not, because that will wash. Surely that.
553 00:59:17.540 --> 00:59:17.860 Andrew Clegg, Martock: No.
554 00:59:17.860 --> 00:59:18.420 tristram cary Winchfield Parish: Through everything.
555 00:59:18.420 --> 00:59:23.830 Andrew Clegg, Martock: Exactly how few is few. That's what we're trying. That's what we're working.
556 00:59:24.790 --> 00:59:31.030 Andrew Clegg, Martock: What we're working on. My guess is that we'll see quite a big difference
557 00:59:31.680 --> 00:59:37.159 Andrew Clegg, Martock: in the 1st year, but that will tail off over time.
558 00:59:37.730 --> 00:59:46.389 Andrew Clegg, Martock: and and but it won't won't get down to almost 0 for decades, maybe even centuries. I don't know.
559 00:59:47.800 --> 00:59:52.250 Andrew Clegg, Martock: This is this is chemistry, phosphate chemistry. It's awkward chemist.
560 00:59:52.250 --> 00:59:59.329 Cllr Stuart Withington, Gt Dunmow-TC, Essex: I would have thought, if it's a sort of chemical equilibrium, it would be a sort of logarithmic decay.
561 00:59:59.400 --> 01:00:26.420 Andrew Clegg, Martock: Yeah, I was going to mention that it should be an exponential decay, and there is one sewage works which is at a place called South Petherton here, which has been now amended. Put right about 6 months ago, and that's what I think we're seeing. But the trouble is, I haven't been able to get out to measure it, because we've had such an odd season in the last 2 months. I haven't. I haven't been doing my usual
562 01:00:26.760 --> 01:00:33.020 Andrew Clegg, Martock: measuring of all the way along the Parrett in a normal day or a normal week.
563 01:00:33.650 --> 01:00:35.359 Andrew Clegg, Martock: because we haven't had a normal week.
564 01:00:36.460 --> 01:00:41.629 Cllr Stuart Withington, Gt Dunmow-TC, Essex: And can I just ask what the water treatment works are doing to remove the phosphate.
565 01:00:41.840 --> 01:00:47.890 Andrew Clegg, Martock: Yeah, it's iron, iron, iron, iron sulfate they're putting in there. They're passing.
566 01:00:47.890 --> 01:00:50.119 Cllr Stuart Withington, Gt Dunmow-TC, Essex: That that collates the phosphate.
567 01:00:50.120 --> 01:01:01.309 Andrew Clegg, Martock: That's right. It chelates the phosphate, and they tell me that it comes out with a they get a chemical which, with very little treatment
568 01:01:01.450 --> 01:01:05.610 Andrew Clegg, Martock: can be converted back into fertilizer.
569 01:01:06.350 --> 01:01:07.739 Andrew Clegg, Martock: The trouble is
570 01:01:07.970 --> 01:01:18.219 Andrew Clegg, Martock: that this country no longer produces its own iron sulfate, because our iron and steel industry is has declined so much now
571 01:01:18.350 --> 01:01:22.400 Andrew Clegg, Martock: that there is, they have to import this iron sulphate from Poland.
572 01:01:23.850 --> 01:01:24.160 Graham Stoddart-Stones - Great Collaboration: Oh!
573 01:01:25.480 --> 01:01:28.439 tristram cary Winchfield Parish: What about sprinkling iron sulphate on the river?
574 01:01:29.500 --> 01:01:42.280 Andrew Clegg, Martock: Yeah, there's all kinds of things like that. Somebody. There's a little company near us that has developed. So I understand some sort of thing that you can put in a small stream
575 01:01:43.330 --> 01:01:45.649 Andrew Clegg, Martock: and remove the phosphate
576 01:01:46.060 --> 01:01:53.980 Andrew Clegg, Martock: from it as it's as the stream flows through it, and that sounds like a nice sustainable
577 01:01:54.240 --> 01:02:01.309 Andrew Clegg, Martock: process. But there, it's that's in early days, and they won't tell me any of the details, because it's all secret.
578 01:02:01.670 --> 01:02:02.320 tristram cary Winchfield Parish: Right.
579 01:02:04.540 --> 01:02:16.529 Graham Stoddart-Stones - Great Collaboration: Very interesting circular thing. I mean, years ago, when I was working in a nuclear submarine, we had ions, sulphate exchange devices which were taking the ion out of the water.
580 01:02:16.530 --> 01:02:16.940 Andrew Clegg, Martock: Yeah.
581 01:02:16.940 --> 01:02:19.780 Graham Stoddart-Stones - Great Collaboration: And here you are, a new little company in Somerset.
582 01:02:20.550 --> 01:02:25.040 Graham Stoddart-Stones - Great Collaboration: something to take the sulfate out of the water, fascinating.
583 01:02:25.040 --> 01:02:25.690 Andrew Clegg, Martock: Yeah.
584 01:02:30.260 --> 01:02:35.969 Graham Stoddart-Stones - Great Collaboration: Well, I did find that fascinating Andrew. Thank you very much indeed for the time, and travel really enjoyed it.
585 01:02:35.970 --> 01:02:37.079 tristram cary Winchfield Parish: Yeah, 1 point.
586 01:02:37.080 --> 01:02:38.559 Andrew Clegg, Martock: Thank thank you for inviting.
587 01:02:39.590 --> 01:02:41.529 Cllr Stuart Withington, Gt Dunmow-TC, Essex: Obviously put a lot of effort into it.
588 01:02:41.680 --> 01:02:42.820 Andrew Clegg, Martock: I'm impressed.
589 01:02:42.820 --> 01:02:48.980 Andrew Clegg, Martock: Well, it's it's it's not not specifically for this presentation.
590 01:02:49.230 --> 01:02:52.039 Andrew Clegg, Martock: It's been my hobby.
591 01:02:52.040 --> 01:02:52.390 Cllr Stuart Withington, Gt Dunmow-TC, Essex: Yes.
592 01:02:52.390 --> 01:02:54.047 Andrew Clegg, Martock: 2 years, now.
593 01:02:54.830 --> 01:02:58.669 Graham Stoddart-Stones - Great Collaboration: But, how many scientists are there around the country?
594 01:02:59.400 --> 01:03:02.716 Andrew Clegg, Martock: There are lots I mean the the
595 01:03:03.390 --> 01:03:13.149 Andrew Clegg, Martock: The I suspect the Stuart is doing the same kind of thing as many, many people are doing down in the west country called West Country Rivers.
596 01:03:13.710 --> 01:03:21.659 Andrew Clegg, Martock: and there must be about probably several 100 doing it in West Country rivers, and I'm 1 of those.
597 01:03:22.310 --> 01:03:22.990 Graham Stoddart-Stones - Great Collaboration: Brilliant.
598 01:03:23.860 --> 01:03:26.790 Graham Stoddart-Stones - Great Collaboration: Well, more power to you, and thank you again.
599 01:03:27.140 --> 01:03:32.540 Graham Stoddart-Stones - Great Collaboration: And I look forward to seeing everyone next week when I could tell you what we're going to see. But I've forgotten.
600 01:03:33.150 --> 01:03:36.750 Graham Stoddart-Stones - Great Collaboration: Okay, take care, everyone. And thank you. Again.
601 01:03:36.750 --> 01:03:37.500 Graham Stoddart-Stones - Great Collaboration: Yeah, Andrea, yeah.
602 01:03:37.820 --> 01:03:38.520 Cllr Stuart Withington, Gt Dunmow-TC, Essex: Thanks, Andrew.
603 01:03:38.520 --> 01:03:39.900 Andrew Clegg, Martock: Okay. Bye-bye.
# Phosphate in the Parrett Catchment
**Great Collaboration - 26 Feb 25**
**Andrew Clegg**
## Acknowledgements
- Natural England, Wessex Water, RSPB, Internal Drainage Board, and the Environment Agency for help and advice with the science, research processes, data collection, and management.
- Wessex Water for Total P sample analysis.
- The Parish or Town Councils of Langport, Huish Episcopi, Martock, Merriott, and Haselbury Plucknett for their support and encouragement.
- Colleagues in Langport and West Sedgmoor for additional sampling data.
- Ash and Martock Nature Recovery.
**February 2025**
---
## A Bit About Me
- Brought up in Yorkshire rural wilderness.
- One-time research chemist.
- Career in Science education, mainly in Africa.
- Now live in Martock - on the River Parrett where it enters the Somerset Moors and Levels (4000 people, 260 listed buildings).
- Guided Martock’s Neighbourhood Plan to fruition (sort-of) in 2021.
---
## The Phosphorus Cycle
---
## The Solubility of Oxygen in Water
- The solubility of gases in water decreases with temperature (not like sugar in tea).
- Water organisms find it increasingly hard to survive as the water warms.
- They need the help of underwater plants to produce oxygen in the water during the day.
---
## What is Eutrophication?
### Stourhead Lake, July 2018
- Blanket algae growing in nutrient-rich water prevent light from reaching underwater plants.
- The water and organisms underneath are starved of oxygen.
- Caused by a prolonged period of hot weather with no rain and little air and water movement.
- Made worse when the algae die and use oxygen during decomposition (eutrophication).
---
## Drought of Summer 2022
- West Sedgemoor, rhynes fed by local streams and irrigation from the Parrett.
- Flow around the rhynes almost halts as evaporation increases and pumping decreases to maintain water levels.
- Much blanket algae and duckweed observed.
- Inset shows hundreds of snails upside down, desperate for air.
---
## The ‘Poor Ecological State’ of the Somerset Levels and Moors (SLMs)
### **Problem**
- Long-term decline in the ecological state of the SLM Ramsar site was deemed illegal by the Supreme Court (‘Dutch N’ case).
- High levels of phosphate were found throughout the Levels and catchment rivers.
- Nutrient neutrality programs had to be legally reflected in all future planning.
### **Implemented Solution in Somerset**
Based on two (untested) assumptions:
1. The SAGIS model (Source Allocation Geographical Information System).
2. The phosphate was delivered to the Levels by the Parrett and its main tributaries – the Tone, Isle, and Yeo.
- A nutrient offsetting program was instituted to make all new buildings nutrient-neutral throughout their lifetimes (80+ years).
---
## River Parrett, Chiselborough
- Weekly trace of PO₄ concentration, PO₄ load, and river flow from May 2023.
---
## What We Have Found Out
- **Baseline summer phosphate load** (at Chiselborough) of about **40kg/day**, mainly due to sewage plants.
- **Defra ‘Rules for Farming near Water’ work well** (when followed).
- **Improvements in sewage treatment** are immediately detectable near the outflow but countered by legacy phosphorus within a few hundred meters.
---
## Healthy Ponds
- Healthy ponds are very effective at removing excess nutrients.
---
## Additional Findings
- Additional phosphate in a flood is mainly due to **‘legacy’ phosphate** in the river sediments.
- **Moor flood water contains a higher concentration of phosphate** than the rivers.
---
## Research Questions Generated
1. Where does the additional winter phosphate come from?
2. Is the state of the Levels due to warming, with phosphate just an exacerbating factor?
3. Does winter flooding wash out phosphate into the Bristol Channel, or is it deposited on the flooded areas?
4. What new paludiculture crops or farming processes would remove phosphate?
5. Can drainage procedures be revised to increase the amount of phosphate moved to the sea (e.g., raising water throughput in summer)?
6. Are there effective ways of re-oxygenating key rhynes – naturally or artificially?
7. Will lowering the phosphate load have any impact on the state of the Levels?
