Table 7.6a     Overall Impact Evaluation to Pak Ngan Heung River.

Evaluation Criteria

Pak Ngan Heung River

Habitat quality

Moderate-high

Species

Potential disturbance and temporary habitat loss for avifauna species of conservation interest, (Grey Heron, Ardea cinerea;  Little Egret, Egretta garzetta; Chinese Pond Heron, Ardeola bacchus; Striated Heron, Butorides striatus; Black-crowned Night Heron, Nycticorax nycticorax; White-throated Kingfisher, Halcyon smyrnensis; and Plumbeous Redstart, Rhyacornis fulignosus).  

 

Potential direct impact, disturbance and temporary habitat loss for fish species of conservation interest (Flagtail, Kuhlia marginata & Predaceous Chub, Parazacco spilurus)

Size/Abundance

Two small sections of the river totaling approximately 175m in length would be directly affected

Duration

Direct impacts would last for the duration of the construction phase, and a period of re-colonisation during the operation phase.

 

Periodic minor disturbance throughout the operation phase due to routine maintenance (e.g., de-silting works).

Reversibility

Direct impacts to river habitat would be reversible; the newly constructed channel sections are expected to provide suitable habitats for aquatic communities previously recorded from the river.

 

Periodic minor increase in disturbance during operational phase would be temporary and reversible.

Magnitude

The scale of the impacts is considered minor-moderate, given the relatively short sections of river affected.

Overall impact conclusion

Construction Phase: Moderate.

Operation Phase: Minor.