Summary
Summary Dam impacts
- Course
- Institution
These are summary notes of the first and second order impacts of dams upstream and downstream. It briefly looks at three different types of dams.
[Show more]
Seller
Follow
shannonhyslop
Content preview
DamsFunction of dams:
Provision of water (seasonality of water availability)
Flood control (limit outflow)
Irrigation (agricultural uses)
Recreation (swimming, fishing, and water skiing)
Hydropower (electricity)
Dams notably affect the flow regime of the stream above and below the dams. These was a peak of
dams built in South Africa in the 70s (large amount of investment), however slowly started to decline
due to the fact that there are only so many places that one can build a dam.
Types of dams:
The type of dam is dependent on the underlying geology, typology and the stream flow.
Gravity dam: solid concrete wall
o So much concrete mass that able to hold back all the water
o The base of the dam wall is wider than the top of the wall
This is due to the large amount of pressure
Concrete arch: curvature in the wall – this curvature is to divert water pressure away from the
centre of the dam wall and into the sides of the dam (into bank)
o Some of the dam wall goes into the valley walls = abutments
Earth dams: interior of the dam wall is clay – this is because it is difficult for water to seep
through clay
o Compact earth material and covered in rocks or broken concrete
This is to stop the impacts of wave action that causes erosion on the dam wall
o Wider at the base of the wall than at the top of the wall
Dam impacts upstream:
1st order impacts
Thermal regime (dams absorb a lot of heat) – challenges the vegetation and organisms that
can live
o Absorb a large amount of heat therefore there is higher amounts of decomposition
and therefore the production of greenhouse gases
Sedimentation – change in flow velocity (decrease as enters the dam and therefore deposit in
the dam = fill up space)
o This has to get removed and can be expensive
Water equality decreases – eutrophication and trace metals from agriculture and mining
2nd order impacts:
It changes the channel form and the substrates in the channel – may be more prone to flooding
or droughts
Plankton – normally low in streams but large amount in dams
o Requires oxygen for production therefore decreases oxygen content for other
organisms
o Is linked to eutrophication
Periphyton – algae growth (use oxygen and decomposition)
Change riparian vegetation
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying these notes from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller shannonhyslop. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy these notes for $2.85. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
75632 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy study notes for 14 years now