the murky world of freshwater

Dis­cus­sion around the state of NZ’S fresh wa­ter isn’t short of an opin­ion or two, but sci­ence is speak­ing out more loudly.

NZ Lifestyle Block - - Contents - WORDS ABBY MATTHEWS ABBY MATTHEWS is an en­vi­ron­men­tal sci­en­tist, and the sci­ence and in­no­va­tion man­ager for Hori­zons Re­gional Coun­cil.

Our new col­umn looks at prac­ti­cal ways you can make a dif­fer­ence on your block, based on sci­ence.

Wa­ter is an emo­tive topic of con­ver­sa­tion. There is an un­der­stand­able re­luc­tance for sci­en­tists to ven­ture into the pub­lic arena when it comes to the freshwater de­bate. Ad­vo­cacy has its place, but in this ‘post-truth’ world, where is the earnest voice of rea­son?

The health of wa­ter­ways is undis­put­edly im­por­tant to the ma­jor­ity of New Zealan­ders. How­ever, re­cent commentary paints a pic­ture of a nation that rests on its lau­rels and drags the chain in main­tain­ing and im­prov­ing wa­ter qual­ity.

De­spite sto­ries of wide­spread and con­tin­ued degra­da­tion of our wa­ter­ways – and there are cer­tainly cases where this is true – it is by no means all doom and gloom. In the Hori­zons re­gion, which cov­ers the Manawatu and Whanganui, we are see­ing en­cour­ag­ing signs of im­prove­ment.

Sci­en­tists gen­er­ally re­port two key mea­sures for wa­ter qual­ity: state and trend.

Re­cent anal­y­sis of 10 and 25 year trends high­lights sig­nif­i­cant im­prove­ments in ni­tro­gen, phos­pho­rus and bac­te­ria at a num­ber of sites through­out the Manawatu-whanganui re­gion. Many of these sites are lo­cated in catch­ments that in­clude in­ten­sive farm­ing.

Novel tech­niques tell us how long it takes for wa­ter (and nutri­ents) to travel from land to wa­ter. We now know that wa­ter takes on av­er­age less than two years to reach streams in the up­per Manawatu catch­ment, and four to seven years to move through ground­wa­ter to the Manawatu River. This sug­gests that the im­prove­ments we are mak­ing to­day may be seen rel­a­tively soon.

Re­duc­ing run-off through stock ex­clu­sion and ri­par­ian plant­ing re­duces in-stream nutri­ents and bac­te­ria, and also pro­vides much-needed habi­tat for fish and bugs. The ben­e­fits of ri­par­ian man­age­ment are well-es­tab­lished, and the Hori­zons Re­gional Coun­cil is tar­get­ing this work to ar­eas where it can achieve the best out­come for each catch­ment.

Emerg­ing re­search sug­gests that the abil­ity for the en­vi­ron­ment to process nutri­ents varies widely. Not all catch­ments are cre­ated equal. In some ar­eas of the re­gion I work in, the en­vi­ron­ment ap­pears to play a sig­nif­i­cant role in at­ten­u­at­ing (re­duc­ing the ef­fect of) nutri­ents be­fore they reach ground­wa­ter bores or wa­ter­ways. As our knowl­edge of the com­plex re­la­tion­ships be­tween soil, ge­ol­ogy, wa­ter qual­ity and ecosys­tems grows, so too does our un­der­stand­ing of the dif­fer­ent levers we can pull to im­prove the health of our wa­ter­ways.

There is no dis­put­ing that many of New Zealand’s wa­ter­ways are show­ing signs of pres­sure. We can­not be­come com­pla­cent. The chal­lenges be­fore us are dif­fi­cult and com­plex.

How­ever, there is much that can be done to im­prove things. In my re­gion, ini­tia­tives such as the Manawatu River

There are sto­ries of con­tin­ued degra­da­tion... but it’s not all doom and gloom

Lead­ers’ Ac­cord drives change by en­sur­ing that ur­ban wastew­a­ter treat­ment plants are per­form­ing as they should, and that farm­ers are im­prov­ing sys­tems and prac­tices to re­duce the amount of sed­i­ment, nutri­ents and bac­te­ria mak­ing their way into our wa­ter­ways.

En­sur­ing ev­ery­one has ac­cess to the in­for­ma­tion Hori­zons col­lects is key. As com­mu­ni­ties, we must have open and hon­est con­ver­sa­tions about wa­ter qual­ity and nat­u­ral re­source man­age­ment. Land, Air, Wa­ter Aotearoa (LAWA, www.lawa. is New Zealand’s web­site for en­vi­ron­men­tal in­for­ma­tion, pro­vid­ing open ac­cess to re­gional coun­cil mon­i­tor­ing data, along with in­for­ma­tion about how this data is col­lected, an­a­lysed and re­ported. LAWA in­cludes live ac­cess to river flow and ground­wa­ter lev­els, the lat­est air mon­i­tor­ing and wa­ter qual­ity re­sults, and in­for­ma­tion on the suit­abil­ity of pop­u­lar spots for swim­ming and recre­ation.

In­sin­u­a­tions of pub­lic ig­no­rance and ap­a­thy made by some in re­cent years are, in my ex­pe­ri­ence, largely un­founded. The peo­ple of our re­gion come from all walks of life, across a range of sec­tors, and hail from both ru­ral and ur­ban com­mu­ni­ties. We are not naive, nor are we com­pla­cent.

As Ki­wis, we’re renowned for our in­ge­nu­ity, our ad­ven­tur­ous spirit, our will­ing­ness to dig deep and find solutions to the tough­est of chal­lenges. We have smart peo­ple, with new ideas, who are en­gaged and for­ward-think­ing. Let’s sup­port them. By pro­vid­ing peo­ple with the right tools and re­sources, we can sup­port grow­ing busi­nesses and the econ­omy while en­sur­ing we take ap­pro­pri­ate steps to care for the en­vi­ron­ment around us. This is ev­ery­thing from ef­fi­cient wa­ter use to im­proved land use prac­tices, ef­fec­tive sep­tic sys­tems to fit-for­pur­pose ur­ban wastew­a­ter treat­ment and stormwa­ter man­age­ment. There are so many ways in which we can make im­prove­ments and play our part in im­prov­ing wa­ter qual­ity.

We are all re­spon­si­ble for the health of our wa­ter­ways. Now is the time to set the fin­ger-point­ing aside and en­gage in open and hon­est dis­cus­sions. Let’s strive to ad­dress what is not work­ing, and also ac­knowl­edge what is. If hon­esty is to be served, then let’s en­sure it is on ev­ery­body’s plate.

There are so many ways in which we can make im­prove­ments to our wa­ter qual­ity

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