More than 20 million gallons of raw sewage spilled into California waterways last year, according to the state Department of Water Resources Control Board. That's not counting the partially treated sewage that makes its way into our water from overflows and sewer system malfunctions.

Many big sewer pipes are old, and many of the sewage treatment plants are antiquated. But the biggest problem faced by sewer systems in California is the tiny pipe called the lateral.

That's the pipe that runs from your home to the street, the small pipes under all of our homes that end up joining the bigger sewer pipes. When those pipes develop cracks, water leaks into them.

Storm water itself would not overwhelm a sewage system, because it's designed to be a closed system. Storm water is not supposed to BE in sewer pipes. So in one way, it shouldn't even matter what the weather is like – storm water shouldn't really mix with sewage at all.

But during a rainstorm, water seeps into your broken lateral pipe, and all your neighbors' pipes, and that rainwater mixes with sewage in the sewer pipes, and the volume of water/sewage can actually build up far beyond the capacity of the sewer pipe. And in the same way, thousands and thousands of gallons of water mixed in with the sewage can swamp a treatment plant during a rainstorm.

That's the number one concern of sewage treatment plants now. And the sewer districts need your help.

Those laterals are owned by homeowners. They're on private land, so the district can't just go in there and tear them up to replace or fix them.

However, most sewer districts offer a service where they will inspect your laterals to check for leaks, and many have started programs where the district will help pay the cost of repairing or replacing those pipes.

Sewer systems are run by local municipalities. Most communities have a local sewer district, and officials at the district can help you inspect and fix your lateral pipes.

Listen to the Sewage Spills Increasing radio report online.

Areas where the oil spread after the spill. See this map and others.

And November's the month last year when the Cosco Busan crashed, leaking 53,000 gallons of black goo into San Francisco Bay.

So biologists will be particularly attentive this November, one year after the oil spill, to see if there's a noticeable dip in the numbers of herring in the Bay, or the number of migratory birds that alight here.

The number of birds harmed by the oil spill is not really known. More than 2,000 birds were killed – but those are simply the birds that were identified, not the total number. Since many dead birds in remote areas were never found, and since predators took away many of the hurt birds, the estimate for the total number of birds harmed by the spill is many times higher than that. So researchers are conducting experiments to determine a provable, scientific estimate of the number of birds killed or harmed by the oil spill.

According to California Fish and Game scientist Julie Yamomoto, it only takes a spot of oil the size of a nickel to harm a bird. It's not just uncomfortable, she says, it's actually lethal – because the oil is like a hole in a wetsuit, and birds that have been oiled become hypothermic. And they also lose buoyancy, so birds can actually sink and drown in the ocean.

All the experiments and data on habitats, fish, birds and other wildlife will be compiled into something called the Natural Resource Damage Assessment.

It's nicknamed NRDA (pronounced "nerd-a") and that's pretty apt. It's a little wonky, to say the least. The data is supposed to be completed by the end of next year, and then the NRDA report is expected to be compiled and submitted sometime in 2010.

Listen to the Oil Spill Anniversary radio report online.

Mary Collins School teacher Blythe Shelley touching
a leopard shark at the Aquarium of the Bay

So, how do the Bay's leopard sharks, soupfin sharks, sevengill sharks, spiny dogfish, and other shark species differ from "non-shark" fishes? Here are a few key distinctions:

#1. You could say that sharks don't have a bad bone in their bodies. In fact, sharks don't have any bones in their bodies. Sharks-along with their relatives skates, rays, and ratfish-belong to a diverse class of fish that have cartilaginous skeletons, unlike the bony skeletons of other fish.

#2. Body shape. If you look at most fish head on, they have a generally oval shape. Sharks, in contrast, tend to be more triangular with a wide, flat under-surface. Their broad pectoral fins give them lift as they move through the water, not unlike the wings of an airplane. This hydrodynamic shape is key to keeping sharks afloat (you'll see why as we move on to difference #3).

#3. Besides bones, sharks lack the air-filled swim bladders that most fish use for buoyancy (If sharks are airplanes, does that mean bony fish are hot air balloons?) Instead, sharks keep afloat with the help of a large, low-density liver, their unique body designs, and the physics of forward motion. If a shark stops swimming it won't necessarily drown-only some sharks need to swim to breath-but it will sink!

#4. While most fish have gills tucked behind a bony flap called an operculum, sharks exhale water through gill slits located behind their head. Five gill slits are typical, but some sharks -like the sevengill shark found in the Bay-have more. Most sharks use ram ventilation to breath, swimming constantly with their mouths open to keep water flowing over their gills. Bottom dwelling sharks, whose mouths may be buried in the sand, inhale water through an opening on the top of their head called a spiracle and pump water past their gills.

#5. A shark's skin is covered with tiny dermal denticles that differ from scales on most fish. As their name indicates, they bear a physiological similarity to teeth. Their unique structure helps reduce drag as the shark moves through the water-in fact, sharkskin helped inspire the high-tech swimsuits we saw at the Summer Olympics.

#6. Most fish spawn by releasing large numbers of unfertilized eggs and sperm into the water. Sharks, in contrast, reproduce via internal fertilization. Depending on the species, they then lay a much smaller number of fertilized eggs, or carry the eggs inside until they hatch, giving birth to live pups.

Old Adobe Elementary teacher Juliet James examining shark teethSadly, these unique creatures are declining all over the world due to overfishing, pollution, loss of habitat from coastal development, and climate change. And that's bad news not just for sharks but also for their ecosystems. Like lions and wolves, most sharks sit atop the food chain as apex predators; thus their disappearance can trigger a cascade of disruption up and down the chain.

All the more reason for us to study up.

UPDATE on 10/23/09: From the San Francisco Chronicle – "Two World War II cargo ships moored among Benicia's fabled "ghost fleet" since the late 1940s will be towed out of Suisun Bay next month, scrubbed clean in dry dock and ultimately sent to Texas to be broken up and sold for scrap".

Read more about the clean-up effort in the Chronicle here.

On the surface of the story, the Ghost Fleet of Suisun Bay (commonly called the "Mothball Fleet" but most accurately referred to as the Suisun Bay National Defense Reserve Fleet) is leaking toxic waste in the form of peeling ship paint containing nasty heavy metals into an already stressed bay ecosystem. Bad guys: Mothball Fleet. Good guys: Enviros who are suing. Simple, right?

But when we began digging into the story, we found the origins of the problem and current impasse to be a bit more convoluted. I'll attempt to quickly summarize: The fleet has been there since the 1940's. It wasn't until 2006 that it came to light that the exterior paint is peeling from the ships and falling into the bay. Many tons of toxic heavy metals have already fallen into Suisun Bay and there's a lot more to be had. Oddly enough, the story was initially triggered by a study that was commissioned by the federal body who oversees the fleet, the Department of Transportation's Maritime Administration, or MARAD for short. So the Contra Costa Times got a hold of a draft of that report and now, the ships are at the center of a different kind of battle long after they've been decommissioned.

Environmental groups (NRDC, Arc Ecology and San Francisco Bay Keeper), community leaders and water regulators justifiably want MARAD to either remove or better maintain the ships so that they are not polluting these waters that serve as both fishing and nursery grounds for several fragile or threatened species. That includes humans who are often out there catching fish for dinner. Historically, MARAD has been regularly removing and dismantling the ships but like most federal bodies whose charter was drafted during WWII, alacrity is not at the top of their mission statement.

Check out a larger map of the fleet

The real issue now seems to be that MARAD has had to completely stop removing ships because they can't clean their hulls of potentially hazardous invasive biological species (to comply with the U.S. Coast Guard's National Aquatic Invasive Species Act of 2003) without scraping more paint into the bay. So, until someone develops a system to clean the hulls that doesn't scrape more paint into the water, the San Francisco Regional Water Quality Control Board says that MARAD can't remove the ships.

The one possible solution that everyone pretty much agrees upon is to dismantle the ships locally so that they don’t have to be cleaned of invasive species. There are currently no ship dismantlers operating on the West Coast but there's a company called Allied Defense Recycling located on Vallejo's Mare Island Naval Shipyard that's chomping at the bit to tear those ships apart. But they've also run into red tape. And while they await permits and approvals from multiple parties, the ships continue to rot and pollute.

It's always easier to write a story with clear heroes and villains. But to me, it does seem that MARAD, environmental groups and water regulators all agree that we have a problem that must be addressed. So, what now? I guess we wait. Perhaps this lawsuit will kick start some aspect of the clean-up process but in the meantime, frustration mounts for all parties involved and many pointing index fingers are suffering from overuse.

Watch the "Ghost Fleet" TV Story online, as well as find additional links and resources. Also, check out the online photo set of the ships and behind the scenes images.

Every year, millions of fish make a strange and harrowing detour through the Skinner Fish Facility, part of the State Water Project's facilities in the Delta.

In my last post, I wrote about my visit to the Banks Pumping Plant, whose giant pumps slurp water from the Delta to help quench California's thirst. As the volumes of water are sucked up, both resident and migrating fish come along for the ride. The Skinner Facility, in operation since 1968, was built to protect fish from being killed at the pumps–an effort that sadly is not as successful as one would hope (more on that below).

I was amazed to learn there is a whole art and science to fish screens, which range from physical barriers–called positive barriers–like perforated plates or wire mesh, to behavioral barriers like sound, light, or other stimuli aimed at keeping fish away. Well-designed screens minimize both entrainment (fish being pulled into the pump or diversion) and impingement (fish being trapped or injured against the screen itself due to water velocity).

Both physical and behavioral barriers are used at the Skinner Facility. Fish being pulled toward the pumps first encounter a trash rack that diverts many bigger fish, along with floating debris. Next, fish encounter a large, v-shaped array of metal louvers. The louvers create turbulence that functions as a behavioral signal, encouraging the fish to swim away into bypass pipes that function, as our tour guide put it, like "a big vacuum system."

From the bypass pipes fish travel to another set of louvers and pipes, concentrating them into a smaller volume of water, and then into holding tanks in a nearby warehouse. Giant, suspended cone-shaped buckets are used to periodically sample the fish, which are identified, counted, and measured. Some 90 species turn up in the facility, including Chinook salmon, steelhead, white sturgeon, and delta smelt. (I asked our guide if delta smelt really do smell like cucumbers. He confirmed it. In fact, when a school of smelt comes through–an event that has become rare–the warehouse smells "like a salad.") When enough fish have been collected, they are loaded into trucks and driven back to the Delta.

Here's the rub. Many fish caught in the pull of the pumps are lost to predation before even reaching the screening facility. Then, the facility does not effectively screen fish smaller than about 1.5 inches, meaning that littler, less powerful species and juveniles are still vulnerable to the pumps. For the fish that make it to the holding tanks, the process is such a trauma–with big and little fish squashed together in the tanks, buckets, and trucks–it's no surprise there are casualties; in fact, the delicate delta smelt often do not survive. And even for fish that make it through the entire process and out the other end, there's a final, fatal hurdle: the trunks routinely dump salvaged fish at the same locations, where more predators have learned to cluster for a free lunch.

Scientists agree that the loss of fish at the huge state pumps–and other pumps and intake pipes throughout the Delta–is a major contributor to plummeting populations. How much water we use makes a difference: The higher the export rates, the more fish are entrained. There also is broad consensus that more state-of-the-art fish screening facilities are needed. That could come with a hefty price tag. But with our fish disappearing, can we afford not to invest in their survival?

The San Francisco Bay is much more of a mystery to scientists than I, at least, had realized. Why? It's simply too hard to peer into. There's no point in scuba diving. The bay is thick with sediment, much of it a legacy of gold mining explosions in the Delta. So if you want to know what's swimming around in those murky waters, you have to go fishing.

At first glance, this struck me as both laborious and tough on the animals – catch and release may spare lives, but not without putting a lot of stress on whatever's on the other end of the line. But when you think about how heavily we humans use the bay – sewage leaks, oil spills, urban runoff, coastal development — it becomes clear we have to take a closer look at how its inhabitants are faring. Sharks are at the top of the food chain, which means they're a great indicator of how everything underneath them is doing.

Of course, tagging is only worth the effort if you catch enough animals to have meaningful data – which means this project requires tenacity on the part of Aquarium researchers. For updates (as well as info on what to do if you catch a tagged shark) check out the Aquarium's website. Also, here's the radio piece we did on the same project.

Watch the "Cool Critters: Sharks of the Bay" TV Story online, as well as find additional links and resources. Also don't miss our behind-the-scenes photos for this story.

Amy Standen is a Reporter for QUEST and Radio News at KQED-FM.

The California freshwater shrimp is 10-legged crustacean in the family Atyidae.

Found only in a handful of Bay Area creeks, the shrimp is a detritus feeder that prefers glides (calm, slow-flowing sections of streams) with undercut banks, exposed roots, and overhanging vegetation. Adult females produce relatively few eggs-about 50-120-that stick to the mother's pleopods during winter incubation. The young measure about 6 millimeters and are released in late spring or early summer. They grow rapidly, reaching up to 2.5 inches as adults and ranging in color from translucent to rusty red.

The species' closest cousin, the Pasadena freshwater shrimp (Syncaris pasadenae), went extinct in the 1930s, leaving the California freshwater shrimp as the only representative of its genus. The California freshwater shrimp was listed under the ESA in 1988. Recently the U.S. Fish & Wildlife Service issued its 5-year review of the shrimp's status. The report concludes that the species is not ready for delisting, as it still faces many of the same threats as 20 years ago: loss of habit due to agricultural activities and development, water pollution, water diversions-even the construction of recreational summer dams for swimming and fishing.

But there is also good news in the report. At the time it was listed, the shrimp was known from 17 streams; it now has been found in 23. In one of these, the number of shrimp surveyed increased from 1,878 in 1991 to 4,407 in 2000. Many of the streams in which the shrimp is found have watershed management plans in place. And the report also acknowledged the ongoing work of STRAW to restore more than 50,000 linear feet of stream bank, creating new habitat for the shrimp-not to mention other native species.

When Congress passed and Richard Nixon signed the ESA in 1973, a little freshwater shrimp was not at the forefront of their minds. But there is an inspiring sense of democracy in the ESA as written: It empowers citizens to petition or sue the government to protect species. And it doesn't discriminate between the big, showy species and the small and obscure-but equally unique and imperiled-ones.

According to the US Fish & Wildlife Service, since 1973 the ESA has protected 99% of listed species from extinction. National Endangered Species Day is coming up May 16. Find out about ways to help celebrate.

Ann Dickinson is Communications Manager for The Bay Institute (www.bay.org), a nonprofit research, education, and advocacy organization dedicated to protecting and restoring San Francisco Bay and its watershed, "from the Sierra to the sea."

photo courtesy of the San Francisco Public Utilities Commission

Those spills got a lot of coverage, including by KQED, so our question was a little broader. Were those spills an anomaly? (Answer: No, they were big, but not unusual.) And how does this happen in as eco-conscious a place as the Bay Area? What would it take to stop it?

The two Mill Valley spills seem to have resulted from a few different problems: overwhelmed capacity, failed alarms, operator error, and probably other factors, too. But the underlying cause is the same, and it’s true of many sewage systems in the Bay Area: These systems — the pipes, the digesters, the pumps – are reaching the end of their useful lives. (Some of the older clay pipes were built in the 1850s!) Few cities are jumping to do the necessary upgrades, and who can blame them? What’s less sexy than an expensive, disruptive construction project that takes place mostly underground, out of sight?

Still, as we say in the piece, we’ve done it before. Those who lived in the Bay Area before the 1970s may remember the stench of raw sewage drifting up through the car window as they crossed the Bay. Thanks to the Clean Water Act of 1972, the Bay is vastly cleaner than it used to be and there are far less spills.

So what will it take to get cities to pony up the cash this time around? Baykeeper is taking the issue to the courts – you can read more about their Sick of Sewage campaign here: http://www.baykeeper.org/

You may listen to the "Sewage Happens" Radio report online, as well as find additional links and resources.

Amy Standen is a Reporter for QUEST and Radio News at KQED-FM.