The EPA wants cities and towns to address a new strategy to improve water quality in the US by reducing stormwater runoff. Stormwater runoff pollutes the nation’s lakes, rivers, streams, creeks and coastal waters, degrades the aquatic habitats and causes downstream flooding. This new strategy aims at promoting use of green infrastructure for environmental and economic benefits: green infrastructure is a cost-effective, sustainable and environmentally-friendly approach to wet weather management. Using green infrastructure can be useful to mitigate overflows from combined and separate sewers, and to reduce stormwater pollution by encouraging implementation in cities and municipal programs.
How does green infrastructure work?
- It treats rain when it falls, captures and filters pollutants by passing stormwater through soils and retaining it on site.
- Stormwater is reused to maintain or restore natural hydrologies.
- It keeps polluting stormwater from entering sewer systems: by increasing the amount of pervious ground cover, green infrastructure techniques increase stormwater infiltration rates, thereby reducing the volume of runoff entering our combined or separate sewer systems, and ultimately the lakes, rivers, and streams.
Some tools used are green roofs, permeable materials, subsurface infiltration, raingardens and rain harvesting systems for non-potable uses such as toilet flushing and landscape irrigation, porous pavement, infiltration planters, trees and tree boxes.
How does green infrastructure benefit the environment?
Green infrastructure can produce environmental, economic, and human health benefits. The benefits of green infrastructure are particularly accentuated in urban and suburban areas where green space is limited and environmental damage is more extensive. Green infrastructure benefits include:
- A decrease in water pollution by a decrease in stormwater runoff volumes
- It improves Human Health : an increasing number of studies suggest that vegetation and green space (two key components of green infrastructure) can have a positive impact on human health.
- It increases economic activity by creating jobs, and neighborhood revitalization
- It induces energy savings with reductions in heating and cooling costs. For example, green roofs reduce a building’s energy costs by 10 to 15%.
- It preserves and restores natural landscape features (forests, wetlands)
- It enhances groundwater recharge - The natural infiltration capabilities of green infrastructure technologies can improve the rate at which groundwater aquifers are 'recharged' or replenished. This is significant because groundwater provides about 40% of the water needed to maintain normal base flow rates in our rivers and streams. Enhanced groundwater recharge can also boost the supply of drinking water for private and public uses.
- It reduces sewer overflow events
- It improves air quality - Green infrastructure facilitates the incorporation of trees and vegetation in urban landscapes, which can contribute to improved air quality
- It creates additional wildlife habitat and recreational space - Greenways, parks, urban forests, wetlands, and vegetated swales are all forms of green infrastructure that provide increased access to recreational space and wildlife habitat.
- It increases land value - A number of case studies suggest that green infrastructure can increase surrounding property values
EPA will develop the use of green infrastructure in ten cities in the US by collaborating actively with local governments, groups, watershed, tribes. These cities are going to be highlighted as models for other cities. Boston is one of those cities. The goal of EPA is to spread the use of green infrastructure across the US to control stormwater.
Learn about Norfolk Ram's stormwater management services here.
If you have any questions about green infrastructure, please contact John McAllister at email@example.com or at (508) 747 - 7900 x 117.
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Information in this article is taken from EPA new release April, 29 2011, by Enesta Jones and Richard Yost.
For more information about this strategy, you can also download the Strategic Agenda to protect waters and build more livable communities through green infrastructure, that EPA released in 2009 about this subject, here : http://www.epa.gov/npdes/pubs/gi_agenda_protectwaters.pdf.
High levels of nutrients and sediment have been plaguing the Chesapeake Bay for several years, leading to many problems. Some measures have been taken and efforts have been made to try to lower pollutant loadings to the Bay, but they have not been very successful and these efforts were partially cancelled by the population boom and a rapid development in the Bay. The Total Maximum Daily Load (TMDL) for the Chesapeake Bay and its tributaries was finalized by the USA EPA on December 29, 2010 and came out in April 2011 with the aim of ambitiously reducing nutrients, sediment and total suspended solids (TSS) entering the waterways. The TMDL is seen as a positive step to improve the condition of the Bay.
The reduction will be achieved in different steps:
- Point and non point sources will reduce pollutant loadings in the next several years
- Implementation measures will be instituted by 2025
- A series of intermediate deadlines to ensure continual progress in the implementation of the TMDL in the next 15 years will be imposed. The ‘’milestones’’, for example, are part of these deadlines. Jurisdictions will start the milestones in 2012.
The TMDL sets also ambitious goals for WWTPs within the Bay’s watershed. Many wonder how the TMDL can impose pollution reductions from non point sources that are not addressed by existing regulatory programs related to clean water. Aggressive efforts have already been made over the years to reduce nutrient discharges from WWTPs and it led to significant decreases in pollutant loadings from non point sources and agriculture. The TMDL requires even better results. Large WWTPs are required to decrease discharges of nitrogen by 27% and phosphorus by 26% from 2009 levels. Agriculture must cut its loadings of nitrogen by 38% and phosphorus by 31%.
HISTORY AND CONSEQUENCES
Over the years, different agreements have been reached to reduce pollutant loads and this effort provided good results. However, it has not been enough because of the presence of nutrients and sediment, water quality and water clarity have consequently decreased since the 1970s. Excessive algal growth and low concentrations of dissolved oxygens are part of the chronic problems of the Bay as well.
MAJOR CUTS EXPECTED BY THE TMDL
- Total nitrogen : a reduction of 25 % compared to the 2009 level
- Total phosphorus : 24% less than in 2009
- TSS : a decrease of 20% compared to 2009
The pollution limits are designed to ensure compliance with state water quality standards.
PROCESS TO ELABORATE THE TMDL
The six states within the Chesapeake Bay watershed: Delaware, Maryland, New York, Pennsylvania, Virginia and West Virginia, and the District of Columbia, worked together to help develop the TMDL. They prepared a Phase I Watershed Implementation Plan (WIP), which gives the outlines to each jurisdiction to meet its allocated pollutant loads. Then, each jurisdiction has until early 2012 to develop its Phase 2 WIPs. The WIPs will include additional detail about nitrogen, phosphorus, and sediment controls at the local level.
The role of EPA is to ensure pollution reductions and to ensure that the jurisdictions enforce the measures. If a plan is inadequate or the progress is insufficient, the EPA may take the appropriate contingency actions and require additional reductions pollution reductions from non point sources such as WWTP. Point sources have achieved enormous reductions of nutrients in the bay, but it would be too expensive and unproductive to rely ultimately on further reductions from WWTPs.
The TMDL is a promising step in the field of pollutants reductions. However, issues like funding, legal and legislative challenges could delay or affect its implementation.
If you have any questions about pollutants, non point sources or WWTPs, please contact John McAllister at firstname.lastname@example.org or at (508) 747 - 7900 x 117.
Information in this article taken from April 2011, article ‘Chesapeake Bay TMDL calls for steep cuts in nutrient, sediment loads‘’ by Jay Landers, published in WE&T.
Designing and maintaining the urban water provision infrastructure is daily work for thousands of people in the US, including associations such as American Water Works Association (AWWA). Providing people with adequate freshwater becomes a challenge with the urbanization of the world. To meet this worldwide challenge, three conditions must be observed:
- Water availability : there must be an adequate volume of water available
- Quality : it must be clean enough to use, either before or after the treatment
- Delivery : the infrastructure must exist to deliver it where it is needed
The demographic reality of rapid urbanization
Rural-to-urban migration and the growth over time of families already in cities lead to an increasing and rapid urbanization. According to United Nations Development Programme (UNDP) 2009, between now and 2050, 3 billion more people will live in cities. This urbanization coupled with climate change, which makes dry periods of the year even dryer, will have consequences on urban water delivery systems.
There are three criteria that must be met to adequately provide residents with fresh water:
- Water availability
In 20 years, humanity has to build an urban water delivery system five times bigger, in terms of people served, than the one that has developed in Europe over the centuries.
Water shortages will become a burning issue in the world. They will result from two different occurences:
- Perennial water shortages: a recent study emphasized that there are 150 million people in cities with perennial water shortages, which means that there is not 100L/person/day available if all water within a greater metropolitan area is harvested. This number is going to rise to 993 million people in consequence of demographic growth and climate change.
- Seasonal water shortages: they are shortages lasting one or more months. They affect 886 million people in the developing world.
These calculations rely on the fact that cities can use all available water, essentially drinking rivers and streams dry. Overuse of these water sources would have consequences with the extinction of many freshwater species and the destruction of the natural benefits of freshwater systems (fishing, recreation). We must leave some baseline amount of water in a river system as an environmental flow to avoid damaging the ecosystem.
The amount of available water on the Earth’s surface compared with the location of major cities in the developing world. Yellow and orange indicate dry areas, green indicates moderate areas, and blue indicates major river systems. Urban areas are shown as red circles, with the diameter of the circles proportional to the population of the urban area.
A study in the journal Ambio (Mc Donald, 2011b) highlighted the fact that water quality problems are a growing issue in even more cities. Because of the urbanization, there is an increasing rate of density (people/hectare) upstream that leads to excessive nitrate concentrations, which is a detriment to drinking water.
Cities have relatively few resources to address water quality and water delivery issues. For example, water delivery challenges must be solved in Africa with roughly 1/200 of the economic resources as would be available in some developed countries.
To combine urbanization and water shortages, cities can use two different means:
- ‘’Gray’’ infrastructure solution: try to find new sources of water while mitigating the environmental impact of further water withdrawal and storage
- ‘’Green’’ infrastructure solution: try to change the way cities use water by using it more wisely. For example : improve the efficiency of agricultural irrigation
The challenge now is to face the coming global urbanization and climate change by finding a sustainable way to provide the cities with freshwater. Professional organizations such as AWWA or US Water professionals can act effectively in that way to find an adequate solution.
Information in this article is taken from October 2011, article ‘’The coming global urbanization: what it means for freshwater provision’’ by Robert McDonald, in Journal AWWA.
Wirral Waters is an expansive Brownfield redevelopment project near Liverpool of an inland dock area that has fallen on hard times.
This project will take place in the East Float area of a docks complex called the Birkenhead Docks complex. The East Float area provides maritime services. The goal of Wirral Waters project is to create new city neighborhoods with their own role and identity, and a new city waterfront of international stature within the East Float neighborhood. This project is expected to induce the regeneration of the sites and communities surrounding the dock complex as well.
In details :
- £4.5-billion (U.S. $ 7.4-billion) project
- 1.4 million m² of mixed-use space (office, retail, hotel, conference facilities, various amenities)
- It is the largest project of the kind ever developed in the UK
- The project will be completed in 30 years
The main aspect of this project and the key of its success as well is the design team, which is composed of urban designers, engineers, architects, and others. They are going to follow the principles of sustainable design, which guide the whole project. Rainwater collection systems will be featured to conserve energy, and measures will be developed to conserve water and to recycle. The government of the UK recognized the ‘’national importance’’ of Wirral Waters and this project is eligible for government support.
To ensure the uniqueness of each of the quarters of the East Float neighborhood, they will be designed by different architecture firms.
Three waterfront spaces will also be created.
The project of Wirral Waters will also include extensive water frontage, a series of floating pontoons, and 2 structures of historical importance that will be preserved and renovated – a former grain warehouse complex converted into apartments and a hydraulic accumulation tower damaged during WWII.
As for the West Float Portion of the site, it will include a new international trade center, part of the Wirral Water development as well, with four buildings. It will be a center for 1,000 businesses all over the world and this will be the largest such facility in Europe.
The Wirral Waters project consists of a huge construction work and of mitigation work as well. The docks were bombed during WWII and there is a high level of industrial activity, thus there is a high probability of contaminants at the Site.
The Wirral Waters project also includes transportation improvements: multistory undergrounds and at-grade parking facilities will be designed. The strategy aims at emphasizing walking, cycling, buses and ferries. Roadways will also be constructed to regulate the speed of travel on the streets of Wirral Waters.
Information in this article is taken from July 2011, article ‘'Wirral Water Brownfield Project will be UK’s largest‘’ by Robert R. Leid, in Civil Engineering News.
Massachusetts and the Northeast, like the rest of the world, are affected by global warming. This alarming phenomenon due to heat-trapping emissions from human activities needs to be tackled. For the past several years, the climate has changed a lot in Massachusetts: spring arrives earlier, the temperatures in summer and in winter are higher, and there is less and less snow in winter. This climate change can have dramatic consequences on the environment, the economy and the quality of life in Massachusetts and it is going to be worse if emissions continue to grow.
Past emissions have already set in motion unavoidable changes. Decisions and emissions choices have now to be made to counteract climate change and protect the future generations from the most severe consequences of global warming.
There are two different emissions scenarios:
- High-emissions scenario : if no efforts are made, fossil fuels continue to be used and heat-trapping emissions are still growing
- Lower-emissions scenario : if there is an increase in the use of clean energy technologies and a decrease in emissions
Climate change may affect Massachusetts and other Northeast States in different ways. However, if the high-emission scenario were to continue, the consequences could be dire. The consequences are:
- Temperature : it could rise 8°F to 12°F above historic levels in winter and 6°F to 14°F in summer by late century
- Precipitations and winter snow : winter precipitation will increase from 20 to 30%, there will be less snow and more rain, more flooding and heavy, damaging rainfall events
- Drought and stream flow : the frequency of short-term droughts will increase and the summer stream flow decrease because of the rise in temperatures and the change in summer rainfall. This will increase stress on ecosystems and water supply in the State.
- Sea-level rise: the global sea-level is expected to rise between 10 inches and 2 feet by the end of the century. This is particularly alarming in Massachusetts where the coast is densely populated: 4.8 Million people live along Massachusetts’ coastline. There will be an increase in the frequency and severity of damaging storm surges and coastal flooding.
Global warming will have many impacts on coastal communities, human health, fisheries, agriculture, forests, and winter recreation. Massachusetts policy makers will have to make decisions to protect the population, wildlife, and critical coastal wetlands.
What can be done by individual households, businesses and governments to reduce emissions ?
Massachusetts and the Northeast are global leaders in technology, finance and innovation and they are a major source of heat-trapping emissions as well. They can launch a national and international progress if they make sustained efforts to reduce emissions.
The main goal is to reduce global emissions below the lower-emissions scenario, that is to say 80% below 2000 levels by mid-century.
State and local governments have to implement effective adaptation strategies to reduce the threat to Massachusetts’ residents, ecosystems and economies. To reach this goal and meet the climate challenge, they have different strategies and policies in the following sectors:
- Electric power: reform and replace the aging inefficient coal and oil-burning power plants that account for almost 40% of Massachusetts’ electric power.
- Buildings: increase infrastructure spending to protect vulnerable neighborhoods in coastal communities, support stronger enforcement of building energy codes and amend zoning laws. Local governments can require that new construction and renovation projects achieve the US Green Building Council’s LEED certification for example.
- Transportation : invest in public transportation, create incentives to purchase low-emission vehicles, promote ‘’smart growth’’ strategies
- Industries and large institutions can install combined-heat-and- power and on-site renewable energy systems to reduce emissions
- Forestry and agriculture: refine the policies in Massachusetts to promote practices that cost-effectively reduce emissions, for example: increase the use of wind and bioenergy.
Massachusetts is exposed to climate change and its consequences. The State now has to meet the challenge of tackling global warming locally by reducing emissions. The State has to act swiftly to ensure the future of the coming generations.
Information in this article is taken from November 2011, article ‘'Massachusetts, Confronting Climate Change in the US Northeast‘’ by John F. Shea, from Mackie Shea O’Brien.