Arroyo de en Medio facts for kids
Arroyo de en Medio is a small stream in California. Its name means "in the middle creek" in Spanish. This stream is about 2.5 miles (4 kilometers) long. It flows from the side of Montara Mountain. Then it empties into the Pacific Ocean near Half Moon Bay at Miramar Beach. The stream helps supply drinking water to the local area. This is because its sandy soil lets water soak in and fill underground water sources.
Water Underground
The area where Arroyo de en Medio starts is called its headwaters. Here, the ground has a lot of decomposed granite. This is like broken-down rock. Underneath this, there are cracks in the solid rock. These cracks hold water, forming underground water storage areas called aquifers.
This underground water then flows into sandy areas closer to the coast. These sandy areas also store water. They get refilled when it rains. This means the stream helps keep local water supplies full.
Where the Stream Meets the Ocean
At the end of Arroyo de en Medio, the stream cuts through a flat area near the ocean. It forms steep banks that are about eight meters deep. Even at its mouth, the stream often dries up in the summer. This is because the flow stops during the warmer months.
However, some water can still be found in the stream during summer. This water comes from things like street runoff, summer watering of gardens, and car washing. The stream's mouth does not have many trees overhead. But it is full of sedges and other plants, making it a marshy area.
Plants and Animals of the Mouth
The streambed at the mouth is covered with plants that need water to grow. These include willow trees, sedges, stream monkey flower, and red alder trees. These plants are important food for many animals.
Many spiders build their webs here, showing there are lots of insects. These insects are food for other animals like salamanders, tree frogs, lizards, and many kinds of birds. Birds also use this area for nesting and raising their young.
In 1989, a study was done here. It did not find any San Francisco garter snakes, which are an endangered type of snake. However, this snake was seen at a nearby stream called Denniston Creek. The area at the mouth of Arroyo de en Medio is protected as a special "riparian corridor." This means it's an important area along the stream.
