GEOG 101 Lecture Notes - Lecture 28: Impervious Surface, Biocide, Waterproofing
Document Summary
Humus (well aged compost) enrichment in gardens and parks (regosols). Carbonate enrichment, primarily from building rubble (strong alkaline soils). Reductomorphic processes as a result of anaerobic (absence of free oxygen) conditions (e. g. methane generation - reductosols). Soil erosion follows a typical course in north america: Spread of impervious surface with urban development. Removal of cover (vegetation) during construction is the most damaging phase, exposing soil to rainfall, also breaking up soil surface. Ironically even compaction speeds up runoff and therefore erosion, leading to gullying and very rapid losses in storms. Erosion also takes nutrients from soil (land) and deposits it in an aquatic system (river, lake, settling pond, estuary, ocean). Vast sediment yields of urban terrain leads to deposition in fluvial systems in broad reaches of slow-moving water (stream beds, lakes, reservoirs, marshes). Rates of transport differ for sands, silts and clays. Clays removed first make water turbid (cloudy/opaque) and deposited in still waters.
