Slow­ing the flow

Is the past be­ing dredged up? asks Mike Handy­side, who hears alarm­ing sto­ries of river habi­tat be­ing de­stroyed in an at­tempt to pre­vent flood­ing


Mike Handy­side hears alarm­ing sto­ries of habi­tat de­struc­tion

SCANDALOUS” AND “per­verse” are words that might be used to de­scribe post-war dredg­ing, but the An­gling Trust (AT) has used them to il­lus­trate re­cent flood de­fence work by En­vi­ron­ment Agency (EA) con­trac­tors and landown­ers in six coun­ties. Ini­tial ev­i­dence of “wan­ton-like” van­dal­ism was un­cov­ered on Lin­colnshire’s River Idle and a Thames trib­u­tary, the River Mole. It has seen es­sen­tial large woody de­bris ripped out, while bank-sta­bil­is­ing trees, a home to pre­cious wildlife, have been torn away, as though a hur­ri­cane coursed the wa­ter­way. The AT quickly alerted 68,000 an­glers and a stag­ger­ing 10,000 en­gaged with its thread on Face­book, lead­ing to the un­cov­er­ing of fresh en­vi­ron­men­tal degra­da­tion in York­shire, Hamp­shire, War­wick­shire and Kent. The flood de­fence bud­get in Eng­land far ex­ceeds in­come from rod li­cences, but is be­ing used in some cases to undo restora­tion work funded by the lat­ter, a clear case of one depart­ment not talk­ing to the other. Royal Tun­bridge Wells An­gling So­ci­ety re­cently re­ceived an EA grant of £2,000 for habi­tat work, in­clud­ing tree plant­ing on the Med­way in Kent. Imag­ine the sur­prise of its mem­bers last De­cem­ber when they helped the EA stock the river, only to ob­serve a sep­a­rate depart­ment of that or­gan­i­sa­tion de­stroy­ing bank­side veg­e­ta­tion just down­stream. “The re­moval of trees and in-river de­bris is par­tic­u­larly per­verse be­cause the EA also funds work to plant river­side trees to shade the water and other pro­jects to in­stall flowde­flec­tors to cre­ate fish­ery habi­tat,” com­mented AT and Fish Le­gal boss, Mark Lloyd, who added: “It con­sti­tutes a scandalous waste of scarce pub­lic re­sources and a dis­re­gard for the sen­si­tiv­ity of the water en­vi­ron­ment.” In the light of the AT’S dis­cov­ery, I wanted to know if any water-tight com­mit­ments had been made by the reg­u­la­tor that would pro­tect other fish­eries. Prior to a meet­ing be­tween the AT and EA, Mark Lloyd told me: “I have had a con­ver­sa­tion with the EA and they have agreed to put in place mea­sures to en­sure that a) in­ter­nal staff and b) ex­ter­nal “stake­hold­ers” (an­gling clubs and ri­par­ian own­ers) are con­sulted be­fore works are car­ried out by the EA and/or its con­trac­tors.” He added, “So, we have won this im­por­tant point.” I have heard much about the the­ory of “slow­ing the flow” and Mark told me that flood de­fence pol­icy was shift­ing in favour of natural flood man­age­ment (NFM). “We would like it [NFM] to go fur­ther up the sys­tem to where the rain­drop hits the field and en­sure that soils are ab­sorbent,” he said. I was keen to find out more and dis­cov­ered that in the murky world of flood re­search, the EA were study­ing the ev­i­dence. Alas­tair Driver, na­tional bio­di­ver­sity man­ager, showed me a com­pelling study from Ex­eter Univer­sity, in which the “re-wet­ting” of Ex­moor mires by block­ing drainage ditches had re­duced peak storm flows by a stag­ger­ing average of 28.5 per cent. As drought threat­ens the south-east, and ex­ces­sive ab­strac­tion blights the south­ern chalk­streams, these pro­jects re­veal how the ground starts to be a sponge again, de­spite hav­ing been ex­ten­sively drained. Water is slowly re­leased and the flow is main­tained dur­ing dry pe­ri­ods. The Pum­lu­mon Project, at the source of the River Sev­ern, blocked ditches, raised the re­ten­tion ca­pac­ity of more than 1,000 hectares, held 155,000,000 litres, and lifted the water ta­ble by an average of 5 cm. Which begs the ques­tion: why is there a po­lit­i­cal ob­ses­sion with flood de­fence, which merely passes flood­wa­ters fur­ther down the catch­ment? The whole­sale clear­ance of in-river woody struc­tures and bank­side veg­e­ta­tion is un­ac­cept­able and can make the prob­lem worse. The EA’S Flu­vial De­sign Guide states, “This prac­tice of­ten in­creases the flood risk down­stream as flood­wa­ters can ar­rive at bot­tle­necks more rapidly.” Surely this work should only, as a last-ditch tool, tar­get crit­i­cal sites, and not be an ex­cuse for con­trac­tors to have a field day, treat­ing lengths of river like build­ing sites, and should be

ac­com­pa­nied by com­pen­satory habi­tat restora­tion else­where. The EA quotes the En­vi­ron­ment Act 1995 and Natural En­vi­ron­ment and Ru­ral Com­mu­ni­ties Act 2006 in its guid­ance on “Con­ser­va­tion Le­gal Du­ties” stat­ing plainly: “We have gen­eral du­ties to pro­tect and en­hance bio­di­ver­sity re­gard­less of spe­cific des­ig­na­tions.” This first trickle of pro­jects that slow the flow show what can be done across the UK to pre­vent flooded homes. I’m not a great fan of so-called “rewil­d­ing” – I sit firmly on the dam – but won’t dis­pute that Mr Beaver holds water back. It is naïve to think that this an­i­mal is an answer, but by cre­at­ing 13 dams on a three-hectare site in Devon, beavers have helped hold back up to 1,000,000 litres of ad­di­tional water, equat­ing to 33 litres of sur­face water per square me­tre of land. Dur­ing storm events, peak flows be­tween water en­ter­ing the site (from agri­cul­tural land) and leav­ing were 30 per cent lower on average, with a 29 per cent longer lag time. While an­glers worry about the im­pact of beaver-made ob­struc­tions to fish mi­gra­tion up­stream, spawn­ing habi­tat is im­proved down­stream. Not only does natural flow reg­u­la­tion take place, re­duc­ing gravel washout, but these ro­dents have proved, un­wit­tingly, that, on average, water leav­ing the site con­tains over 64 per cent less sed­i­ment than that flow­ing in. Sur­vival rates of salmon and trout eggs will be higher in the down­stream stretch as a re­sult. With NFM work­ing, even the NFU is now talk­ing about it. Its re­cently pub­lished The Flood­ing Man­i­festo makes three de­mands of gov­ern­ment: plan, pro­tect and pay. The farm­ers’ cham­pion, of course, ex­pects its mem­bers to re­ceive in­come for help­ing to slow the flow. One word, how­ever, is con­spic­u­ous by its ab­sence: “en­vi­ron­ment”. Other than in the EA’S name, it rarely ap­pears; one men­tion in the in­tro­duc­tion to the credit of farm­ing. Out of nine case stud­ies, only one farmer seems to be prop­erly recog­nised and val­ued for wildlife work: “This work means di­verse ditch and river bank flora can be found.” Ah, so river­bank veg­e­ta­tion could be im­por­tant, af­ter all. But in a neg­a­tive side to the doc­u­ment, the NFU says, “Farm­ers ex­pe­ri­ence a lack of main­te­nance of wa­ter­courses.” Are they ask­ing for the same de­struc­tive flood de­fence work we have just wit­nessed in six coun­ties? Or, worse, they surely don’t be­lieve that a fleet of post­war moth­balled dredgers are go­ing to be greased up and put to use? Wor­ry­ingly, the NFU also talks of “ex­ten­sion or es­tab­lish­ment of new In­ter­nal Drainage Boards” and makes the state­ment: “These [en­vi­ron­men­tal per­mit­ting reg­u­la­tions] en­able farm­ers to un­der­take es­sen­tial river main­te­nance works, such as bank re­pairs, dredg­ing and habi­tat recre­ation with re­duced ad­min­is­tra­tive bur­den. Ex­emp­tions and permits must also be de­vel­oped for groups of farm­ers or landown­ers who un­der­take river main­te­nance within a catch­ment part­ner­ship.” Surely the word “dredg­ing” doesn’t be­long in the same sen­tence as “habi­tat recre­ation”? If groups of farm­ers were al­lowed to dredge to­gether in a whole river catch­ment, would that not con­sti­tute whole­sale dredg­ing? But look­ing for­ward, the NFU may learn lessons from the Nether­lands. “Room for the River”, a Dutch gov­ern­ment plan, will al­low rivers to flood safely at key lo­ca­tions, where agri­cul­ture, farm build­ings, lo­cal roads and in­fra­struc­ture are pro­tected by bunds and el­e­vated plat­forms (terps). The project is mas­sive, but so is the threat of fu­ture flood­ing, which is im­pos­si­ble to con­trol with the largest fleet of dredgers, as we face the ad­ver­sity of an ever-chang­ing climate.

“I’m not a fan of rewil­d­ing but won’t dis­pute Mr Beaver holds water back”

Re­mov­ing wil­lows will have lit­tle ef­fect on this Sev­ern flood. But natural man­age­ment near the river’s source is slow­ing the flow.

Dredg­ing should be a last-ditch tool, tar­get­ing crit­i­cal sites only, to pre­vent homes flood­ing, such as here in mid-wales.

MIKE HANDY­SIDE writes about en­vi­ron­men­tal fish­eries matters. A fly­fisher for more than 40 years, he has spe­cial­ist knowl­edge and ex­ten­sive ex­pe­ri­ence of rough-stream man­age­ment

Hamp­shire’s River Mole: woody de­bris and trees, crit­i­cal for aquatic bio­di­ver­sity, are be­ing de­stroyed in the name of flood de­fence.

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