Effectiveness of grey and green engineered solutions for protecting the low-lying muddy coast of the Chao Phraya Delta, Thailand

Abstract

Coastal protection measures can be categorized into grey and green solutions in terms of their ecosystem impacts. As the use of grey solutions has become a serious issue due to environmental consequences during the last few decades, green/nature-based solutions have become prioritized. This study evaluates the effectiveness of grey and green solutions applied along the eastern Chao Phraya Delta (ECPD) based on historical shoreline change analysis and coastal observations using Light Detection and Ranging (LiDAR) technology. The results from shoreline analysis indicate that nearshore breakwaters installed 100–250 m from the shoreline have successfully reclaimed the coastline with a sedimentation rate of 17–23 cm/y. Meanwhile, sand-sausage-submerged breakwaters were ineffective at stabilizing the coastline during 2002–2010 due to land subsidence. With a low subsidence rate, the rubble-mound-submerged breakwaters can reduce the shoreline retreat rate with a vertical deposition rate of about 5 cm/y. In contrast, use of a bamboo fence, a green solution widely used along muddy coasts, traps sediment at a rate of less than 1.3 cm/y and typically lasts only for 2–3 years after installation. Decomposed bamboo causes environmental degradation so local communities disapprove of the approach. Results reveal that grey solutions are more effective for stabilizing the ECPD coastline and result in less coastal environmental impact than the nature-based solution using a bamboo fence.

Assessing Groundwater Quality for Sustainable Drinking and Irrigation: A GIS-Based Hydro-Chemical and Health Risk Study in Kovilpatti Taluk, Tamil Nadu

“…Extra sodium in the groundwater alters the properties of the soil and decreases its permeability. Based on the percentage of sodium, groundwater was categorized as highly suitable (20%), suitable (20-40%), permissible (40-60%), not suitable (60-80%), and entirely not suited (>80%) [37][38][39]. With an average value of 16 and 12 in the pre-and post-monsoon seasons, the Na% in the study area ranges from 3 to 39 and 2 to 32.…”