#28 Exploring Watersheds

Recap… Most precipitation falls over the oceans because nearly ¾ of our planet is covered in water. So what happens to the ¼ of water that hits land?

Some water hits land and seeps into the ground in aquifers that we can access by wells & springs *If the water doesn’t get absorbed into the ground, then it is called run-off.

https://www.youtube.com/watch?v=2pwW2rlGIa8

*Run-off happens over areas called river basins, also known as drainage basins. *The goal of all run-off is to move from higher land to the lowest elevation, which is the ocean.

*Mountain ranges and gravity are responsible for forcing water to choose a path in which it will flow down. This water will move to low elevations until it reaches a larger body of water. *Each river basin is made up of smaller tributaries or watersheds, watersheds are the place where water drains from mountains, connecting to other bodies of water *Watersheds are separated by mountain ranges. The separation of watersheds are called divides.

Here is an example of River or Drainage Basin Here is an example of River or Drainage Basin. Let’s identify the watersheds How many smaller watersheds are in this river/drainage basin? At least 9, maybe more?

Watersheds flow in a downward direction trying to make it to the ocean. *Watersheds will eventually meet and connect with other watersheds, feeding into a river. The river of water is called a river basin.

After the freshwater runs off the mountain, its goal is to still make it to the saltwater ocean. The place where freshwater meets saltwater is called an estuary.

*Estuaries Estuaries are where freshwater (from rivers, streams, creeks) meets saltwater (ocean) Also known as brackish water Estuaries have twice the life because 2 ecosystems are colliding

Double the breeding & feeding possibilities *Estuaries have…. Double the plant life Double the nutrients Double the breeding & feeding possibilities

So lets draw a model

River Basin Analogy…. A bathtub catches all water falling within its’ sides, a River basin sends all the water falling on surrounding land into a central river and out to an estuary or ocean.

There are two types of estuaries you must be familiar with In your textbook turn to page C117 and read about salt marshes and mangroves Create a venn diagram comparing and contrasting them in your notes

2 types of estuary: SALT MARSH *Atlantic Carolina coasts Stinky cord grass Absorbs tons of moisture MANGROVES *Louisiana & gulf Hurricane proof trees Absorbs tons of moisture

2 types of estuary: SALT MARSH MANGROVES Louisiana & gulf Atlantic Carolina coasts *Nutrient rich soil promotes growth of grasses MANGROVES Louisiana & gulf *Hurricane proof trees due to thick tree roots Absorbs tons of moisture Great breeding grounds--nursery

2 types of estuaries SALT MARSH Atlantic Carolina coasts MANGROVES Nutrient rich soil promotes growth of grasses *barrier against waves *Great breeding grounds MANGROVES Louisiana & gulf Hurricane proof trees due to thick tree roots *Great nursery