The re­cent rash of tor­ren­tial rain­fall across Trinidad con­tin­ues to cast a bright spot­light on the se­ri­ous prob­lems of in­ten­si­fied flood­ing events. The dam­age to sev­er­al homes and busi­ness­es and the im­pact on mu­nic­i­pal in­fra­struc­ture has been dev­as­tat­ing. Prop­er­ly con­vey­ing warn­ings of im­pend­ing storms and floods are ur­gent­ly need­ed to give peo­ple the op­por­tu­ni­ty to be proac­tive in pre­vent­ing dam­age to their prop­er­ty and liveli­hoods (agri­cul­ture). Ini­tia­tives like ear­ly flood warn­ing sys­tems and riv­er flow mon­i­tor­ing can ac­cu­rate­ly as­sess when ex­treme flood risks may oc­cur.

Ac­cord­ing to the Eu­ro­pean En­vi­ron­ment Agency, an­nu­al flood loss­es across the world can be ex­pect­ed to in­crease five­fold by 2050 and up to 17fold by 2080. Giv­en the re­al­i­ty of the vari­a­tions in pre­cip­i­ta­tion lev­els, Trinidad and To­ba­go is cur­rent­ly ex­pe­ri­enc­ing, these flood­ing events and dis­as­ter seems to be es­ca­lat­ing due to cli­mate change and proac­tive mea­sures must be tak­en to mit­i­gate the prob­lem.

Noth­ing says stormwa­ter man­age­ment and ur­ban runoff con­trol like best man­age­ment prac­tices through sus­tain­able wa­ter re­ten­tion and at­ten­u­a­tion basins, cre­at­ing in­fil­tra­tion and stor­age so­lu­tions. There needs to be fur­ther ac­tions on the fea­si­bil­i­ty of sus­tain­able flood re­ten­tion basins across ex­ist­ing flood plains and over­flow ar­eas of the rivers in Trinidad. There should be greater move­ment from the rel­e­vant min­istries and gov­ern­ment agen­cies to re­store flood­plains be­cause of their role in flood pro­tec­tion, wa­ter man­age­ment and na­ture con­ser­va­tion.

Es­sen­tial­ly, what the flood re­ten­tion basins and flood­plains do is re­tain and ab­sorb stormwa­ter, there­by shield­ing near­by vil­lages and towns from the ef­fects of heavy rain­fall. The con­cept of ‘sponge cities’ which can re­tain stormwa­ter, pu­ri­fy it and drain stormwa­ter in a nat­ur­al way is not a new eco­log­i­cal/en­vi­ron­men­tal en­gi­neer­ing con­cept. Rather than ex­ten­sive dredg­ing and chan­nelling or fun­nelling the stormwa­ter runoff away, a ‘sponge city’ ap­proach would re­tain stormwa­ter for its own use (ir­ri­gat­ing gar­dens and farms, recharg­ing de­plet­ed aquifers, re­plac­ing or re­plen­ish­ing wa­ter re­sources, and pro­cess­ing it so that it can be clean enough to use as drink­ing/potable wa­ter) with­in set bound­aries.

This ap­proach (sponge cities) can in­clude green in­fra­struc­ture such as rooftop gar­dens and green roofs by their very na­ture, de­signed to ab­sorb rain­wa­ter and help to mit­i­gate flood­ing. Sus­tain­able stormwa­ter man­age­ment tools such as green in­fra­struc­ture re­duces stormwa­ter runoff and is ben­e­fi­cial for the en­vi­ron­ment, pre­vent­ing sew­ers and sur­face drainage over­flows and re­mov­ing ni­tro­gen pol­lu­tion from the rain­wa­ter. It baf­fles me why per­me­able con­crete and porous as­phalt can­not be ap­plied to cer­tain sec­tions of the built en­vi­ron­ment.

Im­per­me­able sur­faces do not ab­sorb rain­wa­ter, it blocks it, redi­rects it to the drainage net­work, which in turn of­ten be­comes clogged and su­per-sat­u­rat­ed, re­sult­ing in sur­face wa­ter over­flows on­to the roads, high­ways, streets, and pave­ments. Unchecked and un­changed, the flood­ing will con­tin­ue. The con­cept of sus­tain­able drainage makes per­fect sense for sev­er­al parts of T&T.

As part of en­vi­ron­men­tal ini­tia­tives that are un­der­way across the globe, my rec­om­men­da­tion is that im­per­me­able sur­faces (as­phalt/con­crete) be re­placed with per­me­able paving ma­te­ri­als such as grass and gar­dens, porous con­crete. This will al­low the rain­wa­ter to drain in­to the soil. The process, known as in­fil­tra­tion, al­so serves to sus­tain plant life.

Trinida­di­ans and To­bag­o­ni­ans can­not just leave it up to the Gov­ern­ment, mu­nic­i­pal­i­ties, en­vi­ron­men­tal agen­cies, en­gi­neers and ur­ban plan­ners to place an em­pha­sis on green in­fra­struc­ture to pre­vent ur­ban flood­ing. Cit­i­zens must make it their per­son­al re­spon­si­bil­i­ty to adapt to cli­mate change, man­age waste bet­ter, whether it’s re­cy­cling waste sus­tain­ably, col­lect­ing rain­wa­ter from roofs or build­ing gar­dens in and around your homes. It is im­per­a­tive to take the nec­es­sary steps to be part of the over­all sus­tain­able stormwa­ter and rain­wa­ter man­age­ment so­lu­tion through a wa­ter cir­cu­lar­i­ty ap­proach.

Dr Ki­ran To­ta-Ma­haraj is a read­er in Civ­il & En­vi­ron­men­tal En­gi­neer­ing (Wa­ter and En­vi­ron­men­tal En­gi­neer­ing)-As­ton Uni­ver­si­ty Birm­ing­ham, UK & Project En­gi­neer- In­ter­na­tion­al Wa­ter Se­cu­ri­ty Net­work.