Surveyors want govt to declare flooding national disaster
The Institution of Surveyors of Kenya (ISK) has called on the government to declare flooding in the country a national disaster.
ISK President Eric Nyadimo says the flooding crisis, which has claimed over 100 lives so far, needs immediate attention and resources to avert more loss of lives.
"The government needs to declare the flooding a national disaster and bring in the required resources to mitigate the current issues. We recognize that climate change has become a critical and urgent issue affecting our daily lives, demanding immediate attention as a nation," Nyadimo stated.
The surveyors claim that the flooding could have been caused by the clearing of vegetation cover on the riparian reserve leaving it prone to fast-flowing surface run-off, disregarding planning and zoning regulations during property developments and blocking of waterways thus resulting in backflows.
Nyadimo also says the flooding could have been caused by bursting or sudden opening of private dams thus leading to massive overflow of water and over-development by developers without regard to drainages and percolation of run-off water.
"We understand that rapid urbanization and expansion of cities has contributed greatly to the current problem. We note however that solely attributing blame is not the solution. We must proactively respond to this crisis with comprehensive measures, understanding that the likelihood of future, possibly more severe flooding events cannot be ignored," he added.
Mitigating floods
He also urged the government to relook at the policy which allowed high residential density developments on small parcels of land.
"The consequence has been the removal of vegetation that ordinarily slowed the surface runoff and enabled percolation. The aftermath has been very high velocities of surface runoff from these high grounds to lowlands. The existing river channels and drains are inadequate to hold the flood water, consequently flooding homes," Nyadimo said.
"The solution is to relook the width and depth of these channels against the amount of total discharge. In our view, Nairobi and other cities need to have flood surge tunnels with defined depths that can absorb the excess stormwater discharged during heavy rains."
The surveyors want the government to declare all stormwater outfalls as public spaces, control land uses on the riparian reserves and undertake urgent baseline surveys of affected areas through geospatial techniques like aerial survey and mapping.
"Repeat aerial mapping post-flooding should be undertaken to facilitate post-analysis and hydrological studies. We note that continuous observation and data collection will inform future measures that will help curb the situation. The government should ensure regular mapping as we have espoused in the draft Survey and Mapping Policy," he added
The institution has also proposed the utilization of historic satellite data to identify and implement corrective measures such as storm drainage systems, channels, tunnels, dykes, and dams.
"Ensure that we conduct topographical surveys of construction sites before development. The surveys can also be used on all water bodies to determine the highest watermark of which human activities should be restricted. There is a serious need to undertake afforestation drive on the riparian reserves in line the government policy of planting 15 billion trees by 2032," he added.
"County Governments to undertake suitability studies in flood-prone areas before approving development of structures. This can be achieved through zoning of regions within counties. Approved development plans must indicate how internal stormwater is collected and how it connects to outside storm drainage systems. In addition, maintaining of these drainages MUST be done by the developers and enforced by the county governments."
The body has also suggested simple solutions like unclogging blocked drainages and channels and putting punitive measures in place to discourage garbage dumping on the drainage systems.
"The Government should remove all encroachments on rivers and waterfalls. In addition, should control private water dams, some of which we suspect could have opened their dams thus releasing massive amounts of water," Nyadimo added.
"There is a need to enforce the ratio of concrete space to natural space, to ensure easy percolation of water. We urge that concrete should not form 100% of the built-up area and developers should be discouraged from building from beacon to beacon. The approving authorities should encourage developers to use porous concrete blocks for estate roads and parking bays."
ISK says government agencies responsible for the development of infrastructure like roads must plan, design, and implement these structures effectively ensuring proper drainage and continuous monitoring for their proper functioning.
