Tia and Marcus set up their buckets and shovels near the water The sand here is wet but not too wet They pack sand into buckets and carefully flip them over Marcus starts with a big base Each level gets smaller as he builds higher Then he digs a narrow moat He connects it to the lake The water flows around his sandcastle Tia carefully draws lines into her castle’s walls She doesn’t want the sand to crumble She drips watery sand down the other side for decoration She builds small towers They’re perfect for her flags When she finishes her castle she looks at Marcus It will be tough to decide what to do next BEACH BASICS Beaches are strips of land along bodies of water such as lakes or oceans The materials covering beaches such as sand or rocks are usually shaped by erosion Erosion is the process in which water and wind wear down rocks Erosion from the ocean can create steep cliff faces 6
beaches Human construction and falling of sea levels SHRINKING BEACHES Some beaches are threatened by erosion Erosion is often caused by weather systems Rising sea levels are another threat The ocean may rise to cover part or all of some can shrink beaches Houses and businesses may be built on beaches Sand and plants may be removed and replaced with concrete for buildings Beaches are important for slowing down storms coming from the ocean Plants roots help hold a beach’s sand and soil together Without beaches waves could crash into the shore at full power many plants and animals Losing beaches could harm these living things 8 and land For example waves may crash against rocks They may break some of the rock down into tiny particles that become sand Tides or the rising are one of the main causes of changes to beaches So are ocean currents which are flows of water within the ocean The moving water carries sediment This material can plants and more The water pushes the sediment onto the Beaches are also habitats for include sand shells
Gentle waves can help build sand on a beach shore creating beaches in a process called deposition The water also pulls sediment from the shore and carries it elsewhere This erodes beaches Together deposition and erosion shape beaches Different types of waves can affect what happens to beaches Some waves are made when the water is calm These are called constructive waves These waves carry more sediment than they take away They allow water to pull back from the beach The particles of sand 9
