Cedric Stephens | Flood hazard a costly policy failure

T he Gleaner’s lead story last Monday, ‘John’s Hall Flood Leaves Residents Suffering Loss’, with photos of debris-filled streets, aroused my interest. Paragraph 16 of the 17-paragraph article summarised its key points in the words of one resident who has lived there for over half a century: “It was her first time experiencing such flooding in 58 years”. Her house is located directly beside a river which flows through the area.

My browser’s AI ‘robot’ and a human forecaster from the National Meteorological Service presented more information. John’s Hall is in the parish of St James. It is located near Salters Hill and Orange, with coordinates at 18.4285° north latitude and 77.8501° west longitude, approximately. The area, which is about 75 miles (121 kilometres) west of Kingston, and about 13.7 miles (22 km) from Montego Bay, has a population of about 4,930 persons. It is hilly, and landslides are common. Rivers and streams are nearby.

The heavy rainfall and the flooding two Saturdays ago were as a result of the presence of a weather system – a trough – that was located across central and western parishes and remained there for days. The trough created conditions that led to the afternoon showers that inundated John’s Hall.

To mix a metaphor, troughs, and ridges, are used by local meteorologists as frequently as ackee and saltfish and roast breadfruit and/or Johnny cakes are eaten in the average Jamaican household.

The John’s Hall resident did not mention Hurricane Gilbert when she spoke about the area’s flood history. Gilbert occurred 36 years ago. It made landfall near Kingston, according to the Met Service, around 1 p.m. EDT on September 12, 1988, as a Category 4 hurricane.

Its maximum sustained winds were 130 miles per hour (115 knots) and a minimum central pressure of 960 millibars (28.35 inches). Gilbert’s eye traversed the island, only weakening to 125 mph (110 knots) by the time it emerged from its western coast by the late afternoon hours.

Gilbert’s impact on John’s Hall would therefore have been several orders of magnitude more dangerous than last Saturday’s event. Did the resident have a faulty memory or, did John’s Hall miraculously escape the wrath of 130 mph winds and the accompanying rain which would have induced flooding?

Hurricane-induced flooding is treated as an inseparable part of the hurricane hazard by property insurers in Jamaica. United States insurers do not. Their coverage is limited to wind damage. This is because the federal US government provides insurance against hurricane-caused and other kinds of floods, as local migrants to the United States, especially Florida residents, have been finding out.

The Centre for Research on the Epidemiology of Disasters created an emergency events database called EM-DAT in 1988. EM-DAT data shows that flooding was the most frequent disaster event between 1994 and 2013. It accounted for 43 per cent of all recorded events and affected nearly 2.5 billion people. Storms (aka hurricanes) were the second most frequent disaster, killing more than 244,000 people and costing US$936 billion in damage.

Parris Lyew-Ayee Jr and Rafi Ahmad, in their Natural Hazards Atlas of Jamaica, discuss coastal and inland flooding. The former occurs in low-lying areas along the coast which are exposed to flooding from storm surges associated with tropical storms and hurricanes – I called them hurricane-induced – or from tsunamis caused by earthquakes.

Their vulnerability of critical infrastructure table on Page 50 of the atlas is relevant considering the ongoing discussions about the readiness of some schools for reopening because of damage caused by Hurricane Beryl. Schools were not listed among their 506,029 items of critical infrastructure, unlike police stations, fire stations, hospitals and shelters. Nearly eight per cent, 40,150, are acutely exposed to coastal flooding.

Parts of the section on inland flooding provide more insights into the John’s Hall flood. It reads:

Inland floods are the result of a combination of hydrological processes, generally resulting from a rainfall trigger event that exceeds the threshold of the environment to accommodate the increased water input, and topographical controls. There are typically two types of floods: water floods and debris floods. The latter is caused by debris entrained in water and moving fluidly, much like a cement slurry … they make areas impassable. Following the effect of gravity, they pool and collect in areas where run-off is impeded.

Heavy rainfall may cause flooding when precipitation exceeds the ground’s ability to allow for infiltration. High levels of run-off into rivers may lead to these overtopping their banks and flowing over.

The authors found 815 separate references to flooding in newspaper archives between 1834 and 2008. The distribution between parishes in descending order were St Catherine, St Mary, St Andrew, Clarendon and St Thomas. The largely limestone parish of Manchester had the fewest.

This newspaper’s afternoon companion, The STAR, reported on July 8 that “the newly built Green Acres Police Station in Spanish Town, St Catherine, was flooded once again due to heavy rainfall, reigniting concerns about its readiness to house police officers”. Further that, “despite being slated to open in 2021, the station remains technically unsound due to recurring flooding issues. The original construction cost of $250 million, announced by National Security Minister Dr Horace Chang, was supplemented with an additional $70 million in 2022 to address drainage problems. However, recent heavy showers caused by Hurricane Beryl, followed by another weather system, have demonstrated that these issues remain unresolved”.

Notwithstanding this embarrassing and costly failure in the execution of policy, neither of Jamaica’s two daily newspapers mentioned the flood hazard in their recent editorials – ‘Preparing for Earthquakes’ and ‘Towards Strengthening Response to Disasters’. Is it that, in addition to English and mathematics, we are also failing to understand the geography of our island?

Cedric E. Stephens provides independent information and advice about the management of risks and insurance. For free information or counsel, write to: aegis@flowja.com or business@gleanerjm.com