TIDAL CREEK SYSTEM ON TIDAL MUD FLAT OF JIANGSU PROVINCE
Zhang Renshun Wang Xueyu (Nanjing University)
The tidal creek systems are the most noticeable landform of tidal mud flat and have their unique feature in hydrodynamics and sediment ology. There is one of the most perfect flat for development of tidal creek system in Jiangsu mud flat. The authors analysed the aerial and satellite photographs of Jiangsu's mud coast, measured the some geometry of creek systems and tidal basins made correlation analyses between the geometry and the tidal range there and compared the creek systems in Jiangsu province with those in Great Shanghai city, Zhejiang province, Fujian province and others. The conclusions obtained are as follows: 1. The main factors determining develoment of tidal creek system consist of the water volume in-flowing into creek in late ebb phase, surface sediment composition, tidal current and their asymetry, the runoff from land, storm tide and impact of reclamation and other human actions. 2. The most important factor is the channel effect of flow coming into being in late phase of ebb because the thin layer of tidal water which lags on flat converges into creeks in that time. The depth below which the lag water starts to converge into creek is about 5-15 cm- The great current velocity in early stage of flood reforms locally the form of the creeks. 3. Tidal creek system and tidal basin are first order rhythmical landform of tidal flat. There is a creek system in 2.5 km of low tide line on the average in Jiangsu's mud flat. 4. Silty sediment is the most appropriate for creation of tidal creek. 5. The difference among areas of tidal basin with different tidal range is not obvious. But there are best correlations between the density of creek system, the relative width of the creek mouth, the ratio of the creek area of water in low tide with that of its tidal basin, separately, and tidal range. 6. The runoff from land disturbs the developmental process of tidal creek- It breaks the balance between drainage area of tidal basin and discharge inflowing into creek in late ebb phase, and causes great increase to the former.