Rising rivers, rising costs

The Beacon (Gander) - - Editorial - Rus­sell Wanger­sky Rus­sell Wanger­sky writes from St. John’s. He can be reached at rwanger@thetele­gram.com; Twit­ter: @wanger­sky.

It’s all about a pile of dirt. Oh, and some ar­mour stone, too. But mostly dirt.

This year, it’s New­found­land and Labrador’s pile of dirt. But it’s com­ing to Prince Ed­ward Is­land and Nova Scotia, and New Brunswick as well.

It’s be­cause, when it comes to weather, the ground is mov­ing. Oh, and the wa­ter’s rising.

In St. John’s, the provin­cial govern­ment is pre­par­ing to build a wall. Not, like Don­ald Trump, to keep im­mi­grants out, but to hold the flood­wa­ters back.

What’s be­ing planned is a flood­wa­ter berm 480 me­tres long and cov­er­ing some 2.6 acres, to stop what en­vi­ron­men­tal re­ports sug­gest could be the “in­un­da­tion” of the prov­ince’s only ter­tiary care hospi­tal, the Health Sciences Cen­tre. The project’s in the en­vi­ron­men­tal plan­ning stage right now – three years ago, when plan­ning started, the construction cost was ex­pected to be $283,400.

Leary’s Brook is hardly re­mark­able. More an ur­ban stream than a river, it’s hemmed in by marsh and small spruce, by bat­tered peach-leaf wil­low and stunted birch. In most places, it’s only about 10 feet wide, and sports dis­carded shop­ping carts and tossed bi­cy­cles, the lowhang­ing branches on both sides hung with torn drapes of ragged plas­tic bags.

There are ducks, brown trout, os­prey and gulls, and most of the time, it’s a pleas­ant enough flow of fresh wa­ter.

But the brook drains a large water­shed, in­clud­ing paved mall park­ing lots and ranks of sub­di­vi­sion houses in ar­eas that used to be wa­ter-ab­sorb­ing for­est. That means lots of wa­ter can move down­stream quickly – and, as the prov­ince has seen in re­cent years, even more wa­ter than is usu­ally ex­pected.

That’s be­cause, as the en­vi­ron­ment changes, storms sweep­ing up from the south are bring­ing more and more trop­i­cal mois­ture, and much higher rain­falls than in­fra­struc­ture de­sign­ers ever ex­pected. That’s led to a change in what plan­ners call the 100-year fea­ture: de­sign­ing sys­tems to with­stand the peak storm or rain­fall that can be ex­pected in 100 years. (In Cape Bre­ton, they’d call that 100-year event Thanks­giv­ing 2016 – parts of Sydney saw 219 mil­lime­tres of rain fall that day, mak­ing it the wettest day since records started be­ing kept in 1870.)

That kind of rain­fall would con­vert lit­tle Leary’s Brook to a tor­rent, com­pletely cov­er­ing a nearby thor­ough­fare, flood­ing hospi­tal util­ity tun­nels and po­ten­tially flood­ing the hospi­tal it­self.

Changes to flood flows on that small ur­ban river are re­mark­able; while it was thought that the 20-year peak at a bridge just above the hospi­tal was 47.3 cu­bic me­tres per sec­ond, the new flow is al­most half again as high: 68.2 cu­bic me­tres per sec­ond. In the hun­dred-year storm model? Pos­si­ble flow rates have risen from 64.4 cu­bic me­tres per sec­ond to 91.9 cu­bic me­tres per sec­ond.

The hospi­tal is not alone in de­cid­ing to move for­ward with construction to deal with in­creased flood­ing.

The City of St. John’s is con­sid­er­ing berms all along Leary’s Brook and in other parts of the as­so­ci­ated Ren­nie’s River water­shed.

The city is also build­ing a weir to al­low it to use a pond on the river, Long Pond, as a catch­ment to hold flood­wa­ters dur­ing peak rain­falls.

The cost? Around $4.5 mil­lion, give or take, de­pend­ing on which op­tion the city chooses, on top of the quar­ter-mil­lion­dol­lars be­ing spent to pro­tect the hospi­tal.

It’s good ur­ban plan­ning, but it’s something else, as well: it’s con­sid­er­able spend­ing and a tacit ad­mis­sion that the times, and the weather, are a’chang­ing. And that means tax­pay­ers are go­ing to have to find the cash nec­es­sary to help keep base­ments dry, and rivers some­where close to their cour­ses.

The al­ter­na­tive, as Sydney can at­test, can be even more ex­pen­sive. — by Dec. 8, the cleanup price tag there was al­ready $15 mil­lion. And climb­ing.

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