• Aim to prevent impact on Ella-Wellawaya Road

The National Building Research Organisation (NBRO) has commenced the installation of horizontal drains to release trapped water and ensure ground stability in an area allegedly prone to landslides due to water pressure from the release of water to the Uma Oya tunnel.

Speaking to The Sunday Morning, NBRO Director General (DG) Dr. Asiri Karunawardena said that the NBRO had identified significant ground disturbances and was taking steps to address the situation.

“We have initiated a geophysical investigation to comprehend the subsurface profile, water levels, and affected areas. Additionally, as a temporary measure to alleviate water pressure, we are installing horizontal drains to release trapped water, ensuring ground stability. 

“This action is crucial in preventing potential failures that could impact the Ella-Wellawaya Road downstream. Our priority is to uphold road safety and prevent further damage,” he stated.

Dr. Karunawardena said that NBRO experts – including technical engineers, geologists, and environmental specialists – had visited the area to conduct a walkover survey and analysed aerial photographs and maps before concluding that the area was an old landslide zone.

“This area experienced a landslide long ago and the current debris we see is from that event. This indicates that the area remains unstable. In such areas, water levels and seepage are common. 

“In 2019, we observed minor land instability, but after heavy rains in 2023, this instability was reactivated. As a result, we now observe extensive ground disturbances. 

“The primary suspect for this phenomenon is the effect of the groundwater table and water pressure. Residents in the area believe that changes in water pressure and levels may be linked to the filling of the Uma Oya tunnel,” he explained.

Furthermore, the NBRO DG emphasised on the geological challenges in proving the residents’ claims, as there was scant evidence to support them.