Logging the Cache
Your task is to answer a few simple questions:
1. Describe the floodplain here.
2. Describe the sandplain here.
3. What do you think the difference in soils determines?
Once you complete the Earthcache requirements you can post your find without delay, as per the guidelines. You will also need to verify your find by sending me an email providing answers to the questions. This can be through the message centre or via gemmasiemensma@gmail.com
Kinchega National Park
NOTE: There is a vehicle entrance fee to the park.
Kinchega National Park lies within the Darling Geological Basin. It is one of only two national park in NSW situated on the Darling River and includes a large area of floodplain, overflow lakes and channels, lunettes, sandplains and dunes. As such, it is an important example of an Australian semi-arid landscape.
Here you can visit the Kinchega Cemetery and nearby see an example of the border between a floodplain and a sandplain.
Now for the lesson:
Floodplains
A floodplain is an area of land adjacent to a river. Floodplains stretch from the banks of a river channel to the base of the enclosing valley, and experience flooding during periods of high discharge. The soils usually consist of clays, silts, sands, and gravels deposited during floods.
Floodplains experiences occasional or periodic flooding and perform a significant hydrologic role. A floodplain directly influences the magnitude of peak discharge in the downstream reaches of a river during episodes of flooding. In extreme preciptation events, runoff from the watershed enters the trunk river faster than it can be removed from the system. Eventually water overtops the channel banks and is stored on the floodplain surface until the flood crest passes a given locality farther downstream. As a consequence, the flood crest on a major river would be significantly greater if its floodplain did not store water long enough to prevent it from becoming part of the downstream peak discharge.
Sandplains
A sandplain is an area where the soil is sand deposited from elsewhere by processes such as wind or ocean, rather than direct weathering of bedrock.
Sandplains are quite flat. There may be dune systems, and given time and the right conditions these may form eolianite ridges, but other than that there is little to give a sandplain any topographical character.
Inland sandplains are often extremely infertile, because the sand is often low in nutrients when deposited, plus the good drainage means any nutrients are rapidly leached away.
Sources:
http://www.geomaps.com.au/scripts/kincheganp.php#:~:text=Kinchega%20National%20Park%20lies%20within,an%20Australian%20semi%2Darid%20landscape.
https://en.wikipedia.org/wiki/Floodplain
https://www.britannica.com/science/river/Floodplains