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(Peter)north district – relief
1. North district – Catchment factor
• Hong Kong has no large rivers.
• The larger rivers are mainly in the northwest,
including: Shan Pui River, Shenzhen River, Kam
Tin River, Sheung Yue River, and Ng Tung River.
• Mountain
• Low lying
2. The reason of flooding in North district
• Private land developer and government continue
change the use of land in north
• Land area use to dredge water greatly reduces due to
the reconstruction of land.
• In order to continence the work of drain flooded,
government connect the drains directly from Sheung
Shui, Fanling Town Centre to Ng tung river
3. The structure of river in Hong Kong
• Rivers in Hong Kong are generally short and small,
without a distinctive middle course. Typically, the
upper course is steeper, the middle one gentle while
the lower course is nearly flat
• Upper course - steep, many narrow, V-shaped valleys
are formed by the prevailing downward erosion
• Lower course - flat terrain, it is easy cause flooding
4. Shape of river basin in Hong Kong
• From the distribution of tributary(river), three kind of
shape are list below :
• Dendritic Drainage Pattern
• Rectangular Drainage Pattern
• Radial Drainage Pattern
5. • Dendritic Drainage Pattern
the most common drainage pattern
in Hong Kong
e.g. Lam Tsuen River
• Rectangular Drainage Pattern
Appear at regions of the western New Territories
e.g. the upper course of Tuen Mun River
• Radial Drainage Pattern
found on roughly conical mountains
e.g. Sunset Peak
6. The occurrence of Shenzhen River
• Longest river in Hong Kong
• Between New territories and Sham Chun
• Early 90s, lots rainfall lead to flooding
• Main source of flooding in Hong Kong
7. Before the construction of Shenzhen
River
• Bend, meandering
taking place
• Poor drainage of
water
8. After the construction of Shenzhen
River
• Depth of water
increase from 3m to
7m
• Straight
• lower course flow
has upgrade
• Thread of flooding
Eliminate
9. Evaluation
• The problem of flooding reduce.
• Amount of silt bring the problem of flooding again
• Poor maintenance
Editor's Notes
Private land developer and government continue change the use of land in north district, agricultural land was converted into car park, high-rise buildings and Container yard etc.Land area use to dredge water greatly reduces due to the reconstruction of land. Natural land has been paved by hard surface. Lead to rainfalls flow into the river directly. In order to continence the work of drain flooded, government connect the drains directly from SheungShui, Fanling Town Centre to Ng tung river, however do not widen the river channels or open another channels, it leads to problem of flooding
Rivers in Hong Kong are generally short and small, without a distinctive middle course. Typically, the upper course is steeper, the middle one gentle while the lower course is nearly flatAs the upper course is steep, many narrow, V-shaped valleys are formed by the prevailing downward erosionThe lower course has a flat terrain, it is easy cause flooding
上游的支流往下流方向不斷匯合 , 主流與支流連結的夾角小於 90 度,就像樹木的主幹與樹枝一樣。Tributaries from the upper course merge with the main stream at fairly regular intervals. The angle between the major channel and its tributaries is less than 90 degrees, similar to that between a tree trunk and its branchesthe major channel and its tributaries are connected at angles close to 90 degree. This can occur if faults and joints in the bedrock are arranged at right angles, so rivers and streams flow and erode along these lines of weaknessRadial drainage patterns comprise several streams that diverge from the same point. Streams and rivers often radiate in all directions from the peaks of mountains.