From the popular bike path atop Hansen Dam, the view of the basin stretching toward the foothills is pristine, with dense trees shrouding streams and trails largely left to nature.
But horseback riders who frequent the basin's trails hidden by the canopy are often confronted by its ugly underbelly: graffiti, litter, homeless encampments, used condoms hanging from branches -- the aftermath of prostitution going on in the bushes.
They hear of even worse. Just last month, a pregnant woman in her 20s was dragged off the bike path and raped. The suspect remains at large, having fled into the sprawling park.
It's crimes such as these that a small group of police officers -- looking more like motocross riders in their black and white jerseys, helmets and boots -- are trying to quash from atop their Kawasaki dirt bikes.
Going where no patrol cruiser can go, the Off Road Enforcement Unit, little known even within the LAPD despite its nearly 50-year history, traverses the rugged and rural terrain of the San Fernando Valley, including some 165 miles of fire roads and trails.
The unit has seven officers and two sergeants, who mount the dirt bikes a few times a month, spending most of their time otherwise as traditional motorcycle traffic officers.
"They're very useful, more so than horses," said Sgt. Art Gomez of Valley Traffic Division, which the unit is based out of. "They can get up where horses can't."
And they can get places where most people wouldn't think to go, or even knew existed.
Such as inside the Foothill (210) Freeway.
On patrol around the Hansen Dam area on Wednesday, officers rode down into the wash under the freeway overpass in Lake View Terrace, past gang graffiti adorning the abutments, then climbed on foot up its sloped banks, bending under the hulking concrete mass as they made their way toward manholes opening up underneath the freeway itself.
Officer Steve Carbajal, who helps oversee the unit, drew his gun and flashlight and popped his head up into the hollow structure, making sure no one was home.
No one was. But clothes hangers, mirrors, mattresses, empty cans, a book on maps, a charred makeshift torch and all types of junk stretching beyond the flashlight's reach -- indicated that those living inside the mile-long tunnel of darkness were probably not long gone.
"It's a real eye-opener," said Carbajal, adding that the unit had contacted Caltrans to weld up the manholes. "The general public just drives by and they aren't aware of things that are taking place that they can't see with their own eyes."
The unit, a pack of up to five riders scours dusty flood control channels and gritty underpasses as trains or freeway traffic rumble by overhead.
"They're able to get into areas that I'm not able to get to," said Officer Larry Martinez of LAPD's Foothill Division, who requests the unit to patrol the Hansen Dam area due to complaints and ongoing problems.
"Usually what I do is I'll park the car and walk with my partner and we'll look in all the bushes as we're walking along. So with them, it's great."
Around Hansen Dam, a hub of equestrian activity, the unit has cited people who are illegally driving off-road vehicles or walking vicious dogs off leash on horse trails, both of which tend
to spook horses and have been main concerns of the equestrians.
The unit complements the work of a group of civilian horseback riders who voluntarily patrol the area and report issues to authorities or city officials.
"There are a lot of places that people get in and there are bad folks that know the bad areas and they get away from the cops," said Rene Herrera, president of the Foothill Mounted Patrol, a group of about 45 riders.
"They're able to be visible so the bad guys stayed away. We don't have nearly the amount of stuff we had."
People have also shot at wildlife, Martinez said. And prostitutes often meet clients in the bushes. The unit has made drug arrests there and while looking for the rape suspect, arrested a man who was exposing himself to runners in the park.