Urban swamp syndrome : degradation of a high conservation-value swamp from an urban catchment

This study investigates water quality and aquatic invertebrates within two Blue Mountains Upland Swamps on two occasions. One swamp received catchment runoff from a recently upgraded highway in a partly urbanised catchment. The second swamp drains a nearby undisturbed and naturally vegetated catchment. Water chemistry indicates that the swamp receiving urban runoff had major differences in water geochemistry compared to the non-urban swamp with six times higher salinity, pH 2 units higher and highly modified ionic composition dominated by sulfate, bicarbonate and calcium. The natural swamp stream was dominated by sodium and chloride ions. Stream macroinvertebrate samples taken from both swamps revealed significant ecological differences. These results show the swamp receiving highway runoff is suffering from the ‘urban stream syndrome’, perhaps this could be termed the ‘urban swamp syndrome’? Further research is required to investigate measures required to protect such sensitive swamps of high conservation value from the continuing urban development of the area