Management of Sediment in New South Wales, Australia
ABSTRACT The amount of sediment in major New South Wales rivers and reservoirs is relatively low compared to world averages. This is a result of relatively low erosion rates, the sediment coarseness and numerous sediment sinks between the erodingparts of catchments and the rivers and reservoirs. However, in some locations several problems have required attention. These include: sediment blockage of roads and culverts; sedimentation of small reservoirs and recreational lakes; sedimentation on large alluvial fans; river channel damage casued by low sediment supply; and lack of effective government control over soil erosion and sedimentation in the past. Strategies to overcome these problems start with information collection to pinpoint major problems. This enables the preparation of total catchment management plans. These require proper land-use policies, legislation and education of the public for effective implementation.
Denudational history of the south‐central uplands of New South Wales
Summary K‐Ar age determinations on Tertiary basalts provide the basis of a new chronology for part of the south‐central uplands of N.S.W. A master planation surface which truncates a very diverse lithology was formed before Tertiary times, probably during the Triassic. There is evidence neither of the early Tertiary nor mid‐Tertiary planations which figured so prominently in many accounts of the N.S.W. uplands. By the beginning of Miocene times the Lachlan and Wollondilly Rivers had cut to within 80 metres of their present beds. Basalts in headwater valleys show that this part of the Great Divide was well‐established by Eocene times. The sequence of events in this region is strikingly similar to that proposed for the southern part of the Sydney Basin.
An Internet-based Real-time Heavy Rainfall Display System
A new storm warning system, which can be accessed through the Internet and by cellular phones is described. At the time of a heavy rainfall for disaster prevention, it is important that every resident understand how heavy is that rainfall. A real-time heavy rainfall display system designed for all of Japan provides such information (http://www.disaster-i.net/rain/). In that system values for 1-hour precipitation, 24-hour accumulated precipitation, etc. are displayed at every observatory. Advantages are that not only the latest observations but differences from the historical highest records can be seen. Almost all information is displayed by characters so that users have easy access to the system even when the communication network is crowded. Access date for the six months after the system opened shows that the average daily number of accesses of the top page was 306, and the largest number 3078. The maximum number for daily access to all the pages was about 21,500. This is about 2% of the number obtained on the same day for a similar system operated by the Ministry of Land, Infrastructure and Transport (http://www.river.go.jp/).