Bushmans River Banks EarthCache
Hidden : 1/1/2018
Difficulty:
1.5 out of 5
Terrain:
1 out of 5

Size: Size: other (other)

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Geocache Description:


Bushmans River Banks Earth Cache
Welcome to the Bushmans River one of the most Special and Beautiful places to us. Every moment shared here is a complete privilege. Trust you able to soak up and enjoy any bit of the beauty you can and that is the most important thing about all our caches.

This forms part of our Garden Route Earth Cache River Series and various of our other Garden Route Icon series.

The intended value of this particular Earth Cache is to firstly share some the magnificence and stunning tranquillity of the area and spot. Secondly to learn a bit about rivers and how different of their processes and elements work. Thirdly to grasp the importance of preserving an Eco system.

Below are aerial pictures of the Bushmans River Mouth and Upper region of the river:



Bushmans River bridge
The Bushmans river bridge is one of the most fascinating bridge designs I have ever seen. It has been built with pylons on both sides that are near the banks of the river and then reclaimed land in the middle of the river to support the middle part of the bridge on. This is both tremendously sloppy and very damaging to the environment. What should have been done is using pylons across the entire river.

The effects of this are so far reaching that it is almost in-comprehendible and unimaginable. It affects absolutely every element of the biosphere and river system. What this means is that adjustments continually need to be in order to try keep balance and emulate the natural systems the river would experience without the obstacle. Below is a picture of the west end of the bridge where one can clearly see all this.


Processes such as dredging are therefore required in order to try obtain balance and natural functioning of the river. Dredging is discussed in the below links to other earth caches in the series. Although we do not cover erosion extensively in this cache and focus more on the effects of erosion there are still questions on erosion and gradient and more details are discussed in the other caches in the series. They cover different elements on river erosion without duplicating but rather complimentary elements and topics:

Flow modifications
Any obstacles in a river alter the flow, temperature and sediment in river systems. Reduced flow alters aquatic habitats thus reducing or removing populations of fish, invertebrates and plants that depend on the flow to bring food. Reduced flow also decreases tributary stream flow, changing habitats and altering the water table in the stream aquifer. Consequently, riverside vegetation may be affected and decline in numbers. This may affect animal biodiversity, for example, bird species may leave the area if their habitat is lost or altered. Below is a picture of an attempt to correct the imbalance caused:


Rivers are connected systems and making alterations can disconnect one area from another. They also alter the flow, temperature and sediment in river systems. Changes in water temperature due to flow modification can affect insect development by not allowing them to complete their life cycle. Rivers are connected systems, and barriers such as bridges not properly constructed, dams, culverts and floodgates disconnect one area from another. They prevent species such as marine life from migrating, isolating previously connected populations.

Due to the effects of the change in flow river banks have changed dramatically thoughout the river mouth region. This has also happened so much so at the listed coordinates that it has now formed a major ISLAND in the middle of the bridge which completely disrupts the river system. Below are the satellite and map images where you can clearly see the sand banks that never used to be there:



Soil Deposition
Soil deposition by rivers onto their floodplains has influences the river system dramatically. River influence is strongest in terms of organisms on the habitat called the riparian zone and this occurs in the floodplain area. Biological communities in riparian zones are unique, and distinct from those in the other zones in the rivers.


Streams exchange water, nutrients, and organisms with surrounding aquifers. The interstitial, water-filled space beneath river beds, where most active aquifer-river water exchange occurs, is termed the hyporheic zone, and is an important habitat for a number of aquatic organisms The limits of the hyporheic zone vary, and riverine organisms can be found in groundwater up to 2 km from active stream channels.

Referring to River Diagram below one can see a river’s hyporheic zone that consists of water in the interstices below a riverbed. This zone is biologically active, and can function as a refuge for organisms during high-water events.


Gradients in physical characteristics, including flow, depth, substrate characteristics, and light penetration, exist across river channels. These physical differences within a river result in a diverse range of potential niches for aquatic organisms. Because of the heterogeneous nature of riverbeds, the distributions of fish, invertebrates, and algae, tend to form a patchy mosaic that shifts and responds dynamically to high-water events like flooding. One result of this patchiness is that samples of river organisms are notoriously variable.


Small scale differences of Microhabitats
Organisms distribute themselves at even smaller spatial scales than those described above. The size and texture of river substrates influence invertebrate abundance and species richness. These communities respond to different combinations of velocity, depth, and substrate roughness. As is true in other habitats, the distributions of river organisms are additionally influenced by biological interactions.

Upstream migrations of anadromous fish species bring marine-derived nutrients to the lotic environment. Fish carcasses increased insect abundance. Aquatic insects in turn transfer nutrients linking food webs between rivers and their riparian zones. Larval aquatic insects spend weeks, more typically a year, or even longer, in streams before adult emergence. The synchronous insect emergences provide vital nutrition for fish, terrestrial invertebrates, birds, and mammals. Terrestrial insects falling into streams constitute important parts of the diets of stream fish, making up as much as 50% of their diet.

Benthos is the term given to the community of organisms inhabiting the solid floor, or benthic zone of any water body. Functional feeding groups refers to the Feeding guilds of aquatic macroinvertebrates. These include grazers (commonly called scrapers), shredders, collectors, and predators.


Interference
Humans have rapidly introduced a wide array of disturbances to which river organisms have had no previous exposure during their evolution. We have dammed, channelized, diverted, drained, filled, and polluted, streams and rivers. We have removed riparian vegetation, paved extensive portions of river catchments, and isolated river systems from their floodplains.

Protecting our River Systems
The science of life in flowing water is well developed and active. River research is multidisciplinary in nature, and draws from many branches of biology, chemistry, physics, and engineering. Because the vast majority of streams and rivers are in some way managed by human populations, our impacts on these systems can be extensive, as is our potential to improve stream habitat quality.

New river scientists will have important influences on the health of rivers in the years to come. Just as much we can have a drastic positive impact on our river systems and we need to stay encouraged that every small contribution helps like collecting pollution and keeping the environment clean.





Bushmans River Questions

Please take a picture at your favourite spot anywhere near the mouth either side of the Coordinates or along the river and upload in your Log. Please share a picture so everyone can enjoy the collection.

We have kindly provided all the answers for you in the listing. Please return the favour by sharing your answers in your words what your thoughts and understanding is and share some general knowledge through the way you answer and please do not to stress about submitting the answers. The aim of this earth cache is to enjoy and learn.

1 What do you notice about the Gradient of the slopes of ground leading into the river upstream of the bridge. How is the gradient of these slopes different from what we would expect from a conventional river so close to the mouth.

2 What do you see about the size of the sand bank that has formed around the middle section of the bridge (Also looking for a particular word that describes it mentioned in the listing). What do you notice from the aerial images about the size and quantity of the sand banks all along this stretch.

3 How does the way the bridge has been built effect the ecology of a river by the way it has affected the sand banks.

4 What do you notice about the unique nature of the vegetation when looking upstream.

5 What man made construction has been build that is particular to boats on the upstream side of the bridge on the "Kent on see" side of the river (The East side)


Thank you for sharing this area and cache with us. We trust that you enjoyed the Earth Cache and your experience here.

Please have a look at our caching series all along the Wilderness Mouth including the Whereigo caches. They all share a closer experience of the river nature and the environment.

Additional Hints (No hints available.)



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