engineering

Human impact on river systems

Human impact on river systems is a engineering topic covered in the lgStudy science library. This page brings together a partial reference excerpt, illustrations, worked examples, real-world applications and a short study plan, so you can understand Human impact on river systems rather than just read about it. In short: Many river systems are shaped by human activity and through anthropogenic forces. The process of human influence on nature, including rivers, is stated with the beginning of the Anthropocene, which has replaced the Holocene.

Key takeaways

Human impact on river systems belongs to engineering; place it in that map before memorising details.
Learn the definition first, then one example that makes the definition concrete.
Connect Human impact on river systems to a quantity you can measure, compute or draw — that is where exam questions come from.
Reproduce the core statement of Human impact on river systems from memory before moving on to harder problems.

Reference excerpt

Many river systems are shaped by human activity and through anthropogenic forces. The process of human influence on nature, including rivers, is stated with the beginning of the Anthropocene, which has replaced the Holocene. This long-term impact is analyzed and explained by a wide range of sciences and stands in an interdisciplinary context. The natural water cycle and stream flow is globally influenced and linked to global interconnections. Rivers are an essential component of the terrestrial realm and have been a preferred location for human settlements during history. River is the main expression used for river channels themselves, riparian zones, floodplains and terraces, adjoining uplands dissected by lower channels and river deltas.

Human impact The relationship between humans and rivers, which represent freshwater environments, is complicated. Rivers serve primarily as a freshwater resource and as sinks for domestic and industrial waste water. The consequences from this usage occur from diverse activities and root themselves in complex, interdisciplinary systems and practices. Environmental changes in rivers usually result from human development, such as population growth, the dependence on fossil resources, urbanization, global commerce and industrial and agricultural emission. Anthropogenic activities also include discrete elements like the use of fire, domestication of plants and animals, soil development, the establishment of settlements and irrigation. River ecosystems have been transformed downstream from the point of pollution. Active human transformations, river engineering, have altered the river systems and ecosystems.

River engineering

River engineering, a branch of civil engineering, deals with the process of planned human intervention to improve and restore rivers for human and environmental needs. With modern technologies, data collection and modelling, navigation can be improved, dredging reduced and new habitats can be created. River engineering also handles sediment and erosion control, which can be a threat to humankind by destroying infrastructure, hindering water supply and causing major river cutoffs. River training structures will help to modify the hydraulic flow and the sediment response of a river.

Humans have modified the natural behavior of rivers for longer than history is recorded. The management of water resources, protection against floods and hydropower are not new concepts. Regardless, river engineering has changed in the past century because of environmental concerns. The available amount and type of data about rivers has increased which provides more useful information about the behaviour of rivers and their ecosystems. Engineering experts are able to analyse and adapt in a more environmentally conscious way. Renaturalisation projects raise more awareness for the environment, however, rapidly growing and urbanizing population needs to be supplied with enough water resources and hydropower energy, which calls for more sustainable solutions.

River pollution

Water pollution occurs when water bodies, such as rivers, lakes and oceans are contaminated with harmful substances. These substances degrade the water quality and are toxic to humans as consumers and to the environment. The contamination in a river can come from a point source or non-point source pollution. The most common types of surface water pollution are agriculture, sewage and waste water (including stormwater runoff), oil pollution and radioactive substances. The agricultural sector consumes a lot of fresh water and is the leading source for water degradation.

Timeline Most settlements in human history were placed along rivers, developing into riverine cities and traceable by their considerable environmental footprint. The human influence on rivers can be divided into six chronological stages:

Consequences While river engineering can improve the behaviour of the river or hold it back to adapt to our infrastructure, and therefore be rated as positive or negative impact, pollution undoubtedly has a negative impact on our environment. The consequences are very complex and difficult to measure and classify, as often benefits for humankind imply drawbacks for the environment and the other way around.

Indicators Indicators that make the human impact measurable and quantitatively assessable are: artificial water surface ratio, artificial water surface density ratio, disruption of longitudinal connectivity ratio, artificial river ratio, sinuosity of artificial cutoff, channelization ratio, artificial levee ratio, road along river ratio, artificial sediment transport ratio and the integrated river structure impact index.

Material and sediment flux Through anthropogenic impact the material flux of rivers has changed, which enters the sea and has a strong effect on coastal and shelf environments.

Runoff Alternate land use, deforestation, afforestation and different types of river engineering have also led to changes in hydrologic processes, such as runoff. Mushrooming illegal mining activity can, for example, change the soil structure, the pressure-gradient between stream flow and groundwater and the vegetation cover and therefore lead to increased or decreased runoff. In southern Ghana in the Lower Pra River Basin, the percentage of runoff change, which is linked to human activity is approximately up to 66%. Human presence and infrastructure has benefited from river management, by changing and straightening rivers to make the valuable land around them more live-able.

Water quality The consumption of polluted water leads to many deaths. In the year 2015, 1.8 million people world wide died because of water pollution and over 1 billion people became ill. Low-income and third-world communities are especially endangered, because they often live close to industries with high emission. Hazards like waterborne pathogens and diseases spread fast in water surface bodies like rivers and are especially threatening in third-world countries without sewage- and wastewater treatment systems.

… excerpt ends here. Continue reading the full article.

Illustrations

Worked examples

Example 1 — a first encounter with Human impact on river systems

Start with the simplest possible case. Write down what Human impact on river systems claims or describes in one sentence, then invent the smallest concrete situation in which that sentence is true. In engineering, the smallest case is usually a single object, a single equation or a single measurement. Check that every symbol or term in your sentence has a meaning in that case.

Example 2 — changing one variable

Take the situation from Example 1 and change exactly one quantity: double it, halve it, or set it to zero. Predict what should happen to Human impact on river systems before you calculate. Comparing your prediction with the result is the fastest way to find out whether you understand the idea or only the words.

Example 3 — an exam-style question

Typical questions about Human impact on river systems ask you to (a) state it precisely, (b) apply it to given data, and (c) explain a limitation. Practise writing all three answers in under five minutes; the third part is what separates a full-mark answer from an average one.

Applications of Human impact on river systems

In research: Human impact on river systems appears in engineering research whenever the underlying quantities have to be modelled precisely. Papers usually cite it as a starting assumption and then explore where it breaks down.
In technology and industry: Engineering practice reuses Human impact on river systems in design rules, simulations and safety margins. Knowing the idea lets you read a specification sheet and understand why the numbers look the way they do.
In the classroom: Human impact on river systems is common in secondary-school and first-year university syllabi. It links to neighbouring topics Environmental engineering, Hydrology and urban planning, Riparian zone, so understanding it makes those chapters shorter.
In everyday life: Look for Human impact on river systems outside the textbook — in sport, cooking, traffic, electronics or the sky above you. An example you found yourself is remembered far longer than one you were given.

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How to study Human impact on river systems in 20 minutes

Read the reference excerpt below once, without taking notes.
Close the page and write down what Human impact on river systems means in your own words.
Compare your version with the excerpt and mark what you missed.
Work through the three examples above with pen and paper.
Explain Human impact on river systems out loud to somebody else — or to Teacher Smith in the lgStudy chat.

Frequently asked questions

What is Human impact on river systems in simple terms?

Why does Human impact on river systems matter?

Because it connects several engineering ideas at once: it gives you a definition you can apply, a quantity you can calculate, and a way to check whether a result is plausible.

How should I study Human impact on river systems?

Read the excerpt, restate it from memory, then work through the examples and applications listed on this page. The five-step study plan above takes about twenty minutes.

What does this page cover?

It gives you a compact reference excerpt plus original lgStudy explanations, examples, applications and study material on Human impact on river systems.