Surface Water, Rock Holes and Springs

• Surface water is unsafe to drink because it may contain bugs, dirt, rocks, minerals, and/or chemicals.
• Animals may drink and bathe in surface water sources, potentially causing contamination.
• Rainwater tanks collect and conserve water but may contain contaminants from the roof or gutters.
• Rainwater from tanks is suitable for watering gardens and washing cars/clothes.
• If tank water is for drinking, gutters must be cleaned to avoid contamination.
• Waterholes, rock holes and springs provide water from a combination of ground and surface sources.

Rock Holes

• These are surface water features where water is held in a rock or rocky area.
• They are valuable to Aboriginal people in arid Australia.
• Rock holes are a crucial water supply in dry landscapes with little permanent surface water.
• They assist with travel and access to a larger range of resources.

Springs

• Springs occur when water from an underground aquifer comes to the surface.
• The flow rate is affected by water pressure in the aquifer, rainfall, and human usage.
• Spring water is usually clear but can be discolored by minerals in the ground.

Rivers

• Rivers are large natural streams of water flowing over land, essential to human civilization.
• Rivers transport freshwater to people, plants, and animals worldwide.
• They provide transport, water power, and shape the land by carving valleys and canyons.

River Stages

The Upper Course

• Rain in highland areas collects in channels, forming a stream.
• Streams join others, increasing in size and speed.
• A confluence is where two rivers join.
• The river flows rapidly, cuts through the land, and picks up soil and gravel.
• Over time, the river creates canyons and deep valleys.

The Middle Course

• Fast-flowing water causes erosion, making the river deeper and wider.
• The river erodes left and right, forming meanders.
• As the river flows down gentler slopes, it gets larger and slower.
• Soil, gravel, and sand sink to the bottom.
• Sandbars and islands form from accumulated material.

The Lower Course

• The river flows slowly in flatland.
• There’s less water force than in other stages.
• The river drops eroded sediment.
• The river flows even more slowly, dropping more solid material.
• Deltas form as material accumulates where the river enters the sea.

Erosion and Deposition

• Rivers don't travel in straight lines to avoid obstacles and because humans alter them.
• Erosion and deposition change the shape of a river.
• Erosion involves moving materials like soil or rocks by wind or water, known as sediments.
• Deposition is when sediments are dropped off in a new location.
• Moving waters pick up sand, dirt, and other sediments and carry them downstream.
• Rivers turn brown or murky from the materials they carry.
• Sediments are deposited into lakes or oceans at the end of the river.

Meanders

• These can grow until the water erodes away so much of the river's banks that two meanders merge together.
• The water then takes a new, shorter route.
• Over time, deposition of the river's load will block off the old part of the river, forming an oxbow lake.

Explanation of surface water sources, including the risks of contamination. Rainwater tanks can collect water but require clean gutters. Rock holes and springs provide water in arid landscapes and from underground aquifers, respectively.