11. When it rains, the amount of water flowing through the Los Angeles River can increase from 100 million gallons to 10 billion gallons. Water velocities can reach 35 mph and the River can swell to depths of 25 feet.
12. Water Supply Prior to 1960, approximately 80% of rainwater percolated into the ground and replenished underground water supplies. Today, only approximately 8% of rainwater percolates into the ground and like most cities in California, ground water supplies only a small portion (11%) of the water we use in Los Angeles 88% of the water we use today is piped into our homes from other watersheds.
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14. The Glendale Narrows Los Angeles River in the Los Feliz area (Griffith Park on left)
The Los Angeles River is 52 miles long. It begins at the football field of Canoga Park High School where the Arroyo Calabasas and Bell Creek meet. The River runs adjacent to our major freeways – the 101, 134, 5 and 710. The red circle represents the Glendale Narrows. It is the largest soft-bottom section of the River running from Griffith Park and ends just before the Arroyo Seco. River School Day takes place in this section. There are two other natural-bottom sections of River – about 2 miles in the Sepulveda Basin, before the Tujunga Wash in this picture, and about 4 miles in Long Beach, from just below Compton Creek to the ocean.
This is what the Los Angeles River used to look like before it was paved. In fact, the city of Los Angeles is where it is because when explorers came to the region in the Portola Expedition made its way to the area in the 1700s they found a lush, green landscape at the confluence of the Arroyo Seco and the Los Angeles River. Settlers dug ditches, known as “zanja” to irrigate the Pueblo that was built where Olvera Street is today.
Here is another view of the natural Los Angeles River. You can see a meandering River flowing through fields. The Los Angeles River is a seasonal River with water during the rainy season and just a bit during other times of the year. The River has changed courses nine different times during recorded history. (Click) This is what it looked like when it decided to take a different path.
In 1934 and again in 1938 the River flooded, washing homes down from the mountains, knocking out bridges and railroad tracks. At that time the leaders in Los Angeles decided they needed to find a way to prevent floods like this. That is when the U.S. Army Corps of Engineers was called in to begin paving the Los Angeles River. You can see that they dug down deep in many places and created a River encased in concrete.
This is what the Los Angeles River one looked like. And this is what it looks like now at Canoga Park High School.
The Los Angeles River watershed is over 800 square miles and has several sub-watersheds. A watershed is a drainage area where water flows through streets and into stormdrains. Think of a watershed as a funnel with water coming from the top and making its way through the drains that empty into the Los Angeles River.
In the River’s vast watershed there are over 1,500 miles of storm drains that bring water from the streets to the River to the Ocean.
In this slide you see that the Mississippi River gradually moves downhill to the ocean, taking over 2,000 miles to get to sea level. The Los Angeles River flows downward much more quickly. This means that when it rains water runs into the River and moves swiftly through the channel to the ocean. In fact, it was designed to move water as quickly as possible from the streets to the ocean.
And this is what it looks like when it’s been raining and the River is flowing freely. As you can see, it’s important not to go near its banks at this time.
This slide gives you some information about where our water comes from. Because so much of our region is paved, water does not percolate back into the soil as it should. Fresh water flows through our streets, and through stormdrains picking up waste and pushing that waste into the River. All that fresh water is being wasted.
Here is the region known as the Glendale Narrows that we pointed out earlier in the presentation. There is vegetation in this section because the water table is very high and natural springs push up through the soil. The Army Corps tried to pave these sections but Mother Nature won! You can sometimes see water bubbling up through concrete in the section just downstream from the Narrows.
This is what the River looks like during this region.
The lower 20 miles of the River are mostly paved and run through highly industrialized areas.
This is the vision of the River that most people see in the movies. Films such as “Grease”, “Terminator 2”, and “Transformers” were all shot on the River through downtown Los Angeles.
This is a view of the River after it passes through downtown Los Angeles. You can see that it becomes wider and wider the closer it gets to the ocean to accommodate all the water that is being pushed into the system from upstream.
Here is another view of the River between downtown Los Angeles and Long Beach.
And this is where the River becomes natural again, at the Estuary in Long Beach where fresh water begins to mingle with salt water. This is an important area for migrating and shore birds.
Here you can see egrets, red-legged stilts, coots, gulls, killdeer and ducks.
And this is what the area looks like after it rains. All of the garbage from our city streets gets pushed downstream to Long Beach.
Pollution is washed from our streets – trash, copper from car break pads, dog waste, oil and other chemicals that are not disposed of properly. When people don’t clean up after themselves or if they are careless with their trash it ends up in the River and ocean, negatively affecting the fish, birds and mammals that live here.
This slide illustrates the problem that plastic waste has on our natural environment. So many of those plastic bags end up in our waterways. You will see for yourself how many bags are in the River when you clean during River School Day.
You can make a difference and can prevent this waste from getting into the River. Follow these steps.
What do YOU think?
Here is a reminder that there are birds who live in and depend upon the River. This is what it can look like during and just after the rainy season.
And here are some examples of what happens when plastic waste enters the River, flushes out into the ocean, gets carried out into the Great Pacific Gyre and negatively impacts fish, birds and other sea-creatures.
These are some of the birds that you are likely to see down at the River.
And these are some of the native plants that help to create a healthy River ecosystem.
But these invasive species tend to take hold in the River because its ecosystem is out of balance. You will see a lot of arrundo donnax that grows very high. Not only does trash get tangled in the arrundo, but it chokes out native plants.
Steelhead trout once lived in the Los Angeles River. They would come up from the ocean and swim upstream to spawn. The last recorded incident of a steelhead being caught in the River was in 1940. Because so much of the River is paved now the conditions are not right for steelhead. They need cooler temperatures, places where they can rest and eat. Friends of the Los Angeles River often say that when the steelhead return to the River then we know we’ve done our job!
There are many species of fish in the River, none of which are native to the region, like these carp. They grow quite large and you can often see them splash not only in the Glendale Narrows, but sometimes in the concrete sections.
Many people use the Los Angeles River. Near the Los Feliz Golf Course people ride their horses through the River to get to Griffith Park. People are even fishing in the River. And, a group of kayakers made a three-day trip down the River to prove that it can be done. Friends of the Los Angeles River advocates for a swimmable, fishable boatable River. We look forward to a time when we can bring people down to fish, swim and boat!
Welcome to River School Day. This gives you an idea of what the event will look like. We will be conducting a trash sort to determine the types of trash that we find in the River. Here, you can see how many plastic bags were pulled out.
The city of Los Angeles adopted the Los Angeles River Revitalization Master Plan in May, 2007. This plan provides a vision of what the River can look like within the next 20 to 50 years.
Here is the River downtown as it is today, and what we can create in the future – a place where people can gather and enjoy flowing water, ride their bikes, walk and rest.
This is the area known as the Cornfields. It is just next to Chinatown. Here you can see a vision showing a side channel that comes off of the River to create a lake where people can boat.
People are fishing in the River and we wanted to understand what types of fish they are catching, whether they eat those fish and it they do eat them, are they safe to eat?
We discovered that there are several species living in the River and we did toxicity tests to determine whether they contained any harmful chemicals. Much to our surprise and delight, they were surprisingly clean!