Drainage contributing to flooding in western Canada, expert says

Bruce Johnstone in the Leader Post (Regina): An expert on hydrology and climate change believes the recent flooding in Saskatchewan and Manitoba has been exacerbated by the widespread drainage of agricultural lands that have increased water volumes that flow downstream into Manitoba. “The short answer is, yes I do,’’ said John Pomeroy, Canada research chair in water resources and climate change and director of the Centre for Hydrology at the University of Saskatchewan.

Pomeroy, who has studied water volumes on the Smith Creek watershed over the last 55 years, says agricultural drainage of sloughs and other wetlands appears to have been one of the factors in the recent flooding. “The volume of streamflow is basically doubled from what it was if the wetlands had stayed intact in 1958,’’ Pomeroy said. “It looks like the peak flows have increased about 30 per cent from that.’’

Pomeroy said the Churchbridge-Langenburg area has seen it wetlands reduced from 25 per cent in 1958 to 10 per cent in recent years. “There’s been a lot of drainage there ... It gives us some idea of the impact of drainage in a lot of the Assiniboine (River system),’’ Pomeroy added.

Pomeroy said the floods in 2011 and 2014 have seen the confluence of several factors, including multiple days of persistent rainfall in summer, while previous floods were due to excessive snowmelt in the spring.

“This is what’s making it a perfect storm," Pomeroy said. “There’s been a lot of difficulty in estimating the flood peaks because things like this (agricultural drainage) are making older observations more difficult to interpret. So we’re seeing something that is — it’s a cliché to call it climate change — but that’s exactly what this is.”

And he believes the Saskatchewan government should be doing what the Manitoba government has done by bringing in stiff penalties for illegally draining farmland. “Manitoba made it (unauthorized agricultural drainage) against the law on June 10 with really strict regulations and big fines.’...’

A 2011 flood on the Red River in Winnipeg, shot by Shahnoor Habib Munmun, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license 

Drainage ditches can help clean up field runoff

Ann Perry in USDA News: Vegetated drainage ditches can help capture pesticide and nutrient loads in field runoff, U.S. Department of Agriculture (USDA) scientists report. These ditches—as common in the country as the fields they drain—give farmers a low-cost alternative for managing agricultural pollutants and protecting natural resources.

Agricultural Research Service (ARS) ecologist Matt Moore at the agency's National Sedimentation Laboratory in Oxford, Miss., and his colleagues conducted the research. ARS is USDA's chief intramural scientific research agency.

Until recently, the primary function of many edge-of-field ditches was to provide a passage for channeling excess water from crop fields. Many farmers controlled ditch vegetation with trimming or dredging to eliminate plant barriers that could impede the flow of runoff.

But in one of Moore's first studies, he evaluated the transport and capture of the herbicide atrazine and the insecticide lambda-cyhalothrin for 28 days in a 160-foot section of a vegetated agricultural drainage ditch in Mississippi. One hour after he started a simulated runoff event, 61 percent of the atrazine and 87 percent of the lambda-cyhalothrin had transferred from the water to the ditch vegetation. At the end of the ditch, runoff pesticide concentrations had decreased to levels that were generally non-toxic to downstream aquatic fauna....

USDA photo: ARS ecologist Matt Moore has found that vegetated drainage ditches can be a low cost way for farmers to capture pesticides and excess nutrients in runoff from fields.

Cities, prepare for a rainy day

Joanna Masic in China Daily: In recent weeks, extreme weather has taken many Chinese cities by surprise. On July 21, a heavy downpour in Beijing caused extensive flooding and claimed many lives. It also devastated homes and businesses and disrupted transport and essential services. Last week, while floods wreaked havoc in Shiyan, Hubei province, a series of typhoons lashed the cities on China's eastern coast, forcing widespread evacuations and resulting in severe damage and economic loss.

These events have left the public wondering whether urban infrastructure has the capacity to cope with extreme weather and whether weather warning and disaster response systems are adequate.

Chinese cities are not the only ones facing difficulties in preparing for extreme weather and responding to floods. Asian cities are particularly vulnerable because of their high density of population, weak infrastructure and because large numbers of people live in flood-prone areas.

...Urban storm water drainage systems are typically built to withstand the maximum rainfall expected once in a few years. The standards vary depending on the conditions and information available when the infrastructure is designed. However, in many parts of the world, heavy rain is occurring more frequently and with higher intensity. Urban areas are growing faster than the upgrade of designs or increase in infrastructure capacity....

A flood in Shanghai from Typhoon Wipha in 2007, shot by lauraelizabeth, Wikimedia Commons via Flickr, under the Creative Commons Attribution 2.0 Generic license

Sources of flash floods

Borneo Post via Bernama (Indonesia): ...Flash floods being a recurring phenomenon to city dwellers, they have become part of their lives. However, encountering a flash flood can still cause them nightmares. Many motorists who use Jalan Tun Razak, particularly the stretch near the National Library, still remember what happened on Dec 13, 2011.

Exceptionally heavy rain, which lasted for about two hours, caused a flash flood, trapping thousands of motorists heading home from work. The flash flood occurred when Sungai Bunus overflowed its banks and the water spilled onto Jalan Tun Razak and the surrounding areas.

...Flash floods happen suddenly, after which the water level recedes within a short period of time. But what actually causes the flash floods? ... Many point their fingers at local authorities. Others blame narrow rivers and clogged drains. Some say it is due to climate change.

To environmental activist S Piarapakaran, it is unfair to blame climate change for flash floods. Climate change, he said, takes place because of human greed in destroying nature. “It is like when we have fever due to infection. Likewise, it is just natural for earth to adapt to changes in the surroundings. Climate change cannot be stopped. It will continue until equilibrium is achieved. “But with technology we can be more prepared to mitigate the effects of climate change,” he said.

Piarapakaran said flash flooding is closely related to the clearing of forests to fulfill the country’s growth and development. ... “This has directly increased the surface water flow (rain water that flows on top of earth’s surface) during rainfall,” he explains....

A 1900 Tropenmuseum image of a flood in Western Sumatra, via Wikimedia Commons

Philippine city facing drainage, flooding woes

Judy Partlow in the Visayan Daily News (Philippines): Dumaguete Mayor Manuel Sagarbarria said the city is facing a big problem with its drainage system that is not designed to accommodate huge amounts of rain, but has put much of the blame on excessive rainfall brought on by climate change.

Sagarbarria also admitted in a recent interview that the city does not have the money to improve or build a better drainage system, in order to avoid a repeat of the massive flooding on June 30, that submerged many parts of the city.

He said one of the biggest problems of the city is that its drainage canals are too small. However, it will cost millions of pesos to revamp its drainage system, he added.

A farmer himself, he is apprehensive over the amount of rainfall in Dumaguete, noting that several years ago, the city only recorded about six or seven inches of rain in a month’s time. Nowadays, the city experiences rainfall of two to three inches within an hour to two hours, due to climate change, he added. He said they can only do the regular de-clogging of these canals, now, and that, since last year, at least 22 people have been mobilized by the city to regularly clean out the drainage canals...

Robinson's Place in Dumaguete, Visayas, the Philippines. Shot by Mike Gonzalez (TheCoffee), Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license

Hermosa Beach storm water filtration system wins EPA award

Douglas Morino of the Daily Breeze (California): For years, a project to transform Pier Avenue in Hermosa Beach into a pedestrian friendly-haven was studied and scrutinized. Now that the multimillion-dollar remodel of the beach town's main drag is complete, it's the work done below ground that's getting most of the attention.

A public works project that collects storm water under the busy street and filters it with sand to irrigate landscaping has earned a national award from the federal government. City engineers spent nearly six years developing and working on the ambitious project, which includes a storm drain and water filtration system that keeps polluted water from reaching the ocean and allows it to be reused. The storm drain and infiltration system, part of the Pier Avenue Beautification Project, earned a 2010 Environmental Achievement Award from the U.S. Environmental Protection Agency. The award was announced Thursday during a ceremony at Union Station in Los Angeles.

…The award-winning system uses gravity and sand to naturally collect and filter storm water, which is captured in one of 30 sidewalk drains - or infiltration basins - along the city's main drag. Contaminants, including leaves and trash, are filtered from the water in each of the basins, which are later cleaned out by city workers. Once captured, water saturates the soil below ground, which works as a sponge and natural filter.

From there, water is funneled through plastic pipes buried about four feet underground to the center of Pier Avenue, where it provides deep root irrigation along the street's landscaped median. No water is returned directly to the ocean.

"The project was innovative because rather than just putting in a traditional storm drain, (city engineers) thought outside the box," said Kathleen McGowan, a city-hired consultant who worked on the project. "I think it can be a model for what can be done in the South Bay."...

Hermosa Beach, shot by Christophe.Finot, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 2.5 Generic license

Stormwater model to inform regulators on future development projects

North Carolina State University News: North Carolina State University researchers have developed a computer model that will accurately predict stormwater pollution impacts from proposed real-estate developments – allowing regulators to make informed decisions about which development projects can be approved without endangering water quality. The model could serve as a blueprint for similar efforts across the country.

“The model is designed to evaluate the amount of nitrogen and phosphorus found in stormwater runoff from residential and commercial developments – particularly runoff from a completed project, not a site that is under construction,” says Dr. Bill Hunt, an associate professor and extension specialist of biological and agricultural engineering at NC State who helped develop the model. “To comply with regional water-quality regulations, cities and counties have to account for nutrient loads,” Hunt says, “but the existing tools are antiquated and aren’t giving us sufficiently accurate data.”

The new model is designed to evaluate the amount of nitrogen and phosphorus found in stormwater runoff from residential and commercial developments.

The researchers developed the model using chemical, physical and land-use data specific to North Carolina and surrounding states. This allowed them to account for regional conditions, which will improve the model’s accuracy. “Because the model uses regional data, it could be modified easily for use east of the Blue Ridge Mountains in North Carolina and adjoining states,” Hunt says.

The model could also serve as a blueprint for similar efforts nationally. “The primary obstacle to applying this model outside North Carolina – in Florida or Colorado, for example – would be collecting relevant data from those areas and incorporating it into the model’s framework,” Hunt says. “The actual model itself would be fairly easy to modify.”…

Clogged drainpipes in El Paso, Texas, shot by Robert Alvey for FEMA

Recovery Act funds Washington stormwater projects worth $5.6 million

Environment News Service: Governor Chris Gregoire and the Washington state Department of Ecology have approved clean water projects in Olympia, Spokane, and Seattle's Ballard neighborhood worth a total of $5.6 million in American Recovery and Reinvestment Act funding. The funding will pay for low-impact development projects that provide enhanced stormwater treatment. These projects capture or slow stormwater runoff allowing it to infiltrate back into the ground.

The goal is to prevent polluted runoff from getting into downstream waters and drinking water. The projects will reduce flooding and sewer-stormwater overflows, and improve water quality for threatened and endangered salmon. Project proponents estimate the projects will support about 75 construction jobs. "Getting more jobs is a great bonus, but so is getting the clean water these projects provide for our state and for our salmon," said Governor Gregoire.

Polluted stormwater is the leading cause of urban water pollution in Washington state because water that goes into storm drains is not treated. Washington's capital city of Olympia will receive $3.67 million for enhanced treatment of stormwater runoff at Yauger Park. Half of the $3.67 million is a low-interest 20-year loan and half is forgivable principal loan, or money that does not need to be repaid.

….The project will increase stormwater storage at Yauger Park, reducing erosion from flooding. The project includes low impact development, a water quality treatment wetland, retention ponds, a 5,000 square foot rain garden, and swales. The city also will create a new parking lot using porous pavement.

The eastern Washington city of Spokane will receive $382,000 for its West Broadway SURGE (Spokane Urban Runoff Greenway Experiment) project. Half of the $382,000 is a low-interest 20-year loan and half is a forgivable principal loan, or money that does not need to be repaid.

…Seattle Public Utilities’ Ballard Green Streets project gets $1.54 million. Half of the $1.54 million is a low-interest 20-year loan and half is forgivable principal loan, or money that does not need to be repaid. Using this funding, the utility will install 10 blocks of swales to naturally detain and infiltrate stormwater. This Green Streets project will control runoff from 2.6 acres of hard surfaces, reducing sewer-storm overflows. The swales also will free up capacity in the combined sewer-storm system, further reducing pollution overflows….

Spokane Falls, from an 1888 illustration