Wednesday, February 3, 2010

"B" Layer: Have flood controls on the Mississippi been sucessful?

  1. Levees will block the water like a wall from a certain spot and keep the river flowing in the direction chosen. Modifying the banks will help with river control because they will be stronger or change the direction of a river depending on what the people want to do to modify it. Canals are used to help divert flood water. Revement helps stabilize soil along the banks to make the banks stronger and harder to erode. Dredge makes the river deeper and move slower by turning up sediment from the bottom. Snag boats remove objects obstructing a rivers flow. Dams are built to control flooding.
  2. Floods cause property damage by removing houses by the flow of the water, causing water damage in houses, and removing natural features.
  3. The water levels of the river were 50-100ft above normal in most places and most of the attempts to save sities and towns failed except for the dynamiting of Caernarvon, Louisiana which saved the city of New Orleans and many towns down stream because it released pressure on the flood walls.
  4. There were 29 sets of locks and dams, hundreds of runoff channels, and 100 miles of levees which is more than any amount of flood prevention techniques put into place.
  5. The events that took place in the flood of 1937 were like the flood of 1927 in the fact that they destroyed farmland, towns, cities, houses and anything of the sort in its path. Some of the levees held up and some of them didn't. The control techniques were more effective than the ones that happened before the flood of 1927.
  6. Farms, farmland, houses, bridges, and roads were some of the disastrous events that occurred in the flood of 1993 things that contributed to the flooding events were heavy rains, snow packs, and the moist soil.
  7. Before the flood, there were numerous crops, and they were all bright green on the key of the satellite. During the flood almost all of the landscape turned black (flooded) according to the key for the satellite. After the flood, the landscape is red because the water had receded and deposited a layer of soil as it receded.

"B" Layer: How does stream flow change over time?

1) Factors that control how much water is flowing in a river are:
  • What season (If snow is melting, then it drains into rivers. If its summer, then the water is flowing slower because there hasn't been much runoff going into the river)
  • Rain/snowfall (heavy rains or snowfall add to the amount of water the tributaries pour into the main river)
  • What climate (If it is a very arid climate year round, then there is less water being added to the river such as the Colorado River. If it is wet, there is more water being added to the rivers such as parts of the Amazon River.)
2) In Rillto Creek, Arizona it is stated on the picture itself that it was a flood that occurred to make the water rise so much, but to cause the flood, there might have been heavy rains for an amount of time. In the Mississippi and Wisconsin Rivers, it was snowy in the first picture, and then a month later there was no snow and the rivers were wider so that must of been because of the runoff which drained from the tributaries into the main rivers. At the Colorado River, Glen Canyon Dam, the water was calm and motionless in the first picture, then in the second picture the water was flowing very, very fast which meant there must have been a flood due to heavy rains.

3) That there was a substantial growth in the amount of discharge during that period of time.

4) 3cfs on the 10th of August and 1cfs on the 16th of August

5) The amount of rainfall per mm at a certain time.

6) August 8-11 with about 35mm of precipitation and August 14-16 with about 28mm of precipitation

7) Discharge:
  • August 2nd with 5cfs
  • August 10th with 30cfs
  • August 16th with 10cfs
  • August 27th with 1cfs
  • August 29th with 1 cfs
Precipitation:
  • August 1st with 1.5mm
  • August 7th with 1.3mm
  • August 10th with 3.2mm
  • August 13th with .2mm
  • August 15th with 2.8mm
  • August 27th with 1.5mm
  • August 29th with .9mm
Whenever there is a lot of precipitation, the discharge increases.

8) When the temperature was higher in March, there was more discharge. I conclude that the higher the temperature, and the time of year with the snow melting, the discharge will be higher. I would need to know how much the change of the discharge from the tributaries is.

9) When the rainfall was steady, there wasn't much change in the amount of discharge. So I conclude that if the rainfall is steady, then there isn't much change in the discharge.

10) According to these graphs, there isn't much of a relationship between temperature and discharge because the the temperature is scattered all over the graph, and the discharge is steady until March 30th. There isn't much to conclude from this.

11) I believe that the discharge peaks are regular because people control how much the discharge is because it is passing through a dam. I believe that because of the major runoff in march the had to increase the discharge to accommodate with the water levels of the lake behind the dam.

12) From February 19-29, 2000 the temperature was higher, and the discharge was greater, there was less snow, and less precipitation.