24 April 2013

Urban stream syndrome



Definition:
Urban stream syndrome describes the consistently observed ecological degradation of streams draining urban land.  Symptoms of the urban stream syndrome include a flashier hydrograph, elevated concentrations of nutrients and contaminants, altered channelmorphology, and reduced biotic richness, with increased dominance of tolerant species.

Examples:
The most obvious hydrologic changes associated with urbanization are the engineering of stream channels, in which natural features are replaced by concrete channels and streambank stabilization efforts designed to resist increased flood flows.  Extensive piped storm drainage networks often completely bypass riparian zones, channeling large amounts of water from impervious surfaces directly into streams, both quickly and with increased frequency.  A result of this altered hydrology is that incision or “downcutting” is a common feature of urban stream channels.  Downcutting results from large volumes of water scouring out sediment that has accumulated during agricultural activity and/or residential construction in the watershed.  Incision is especially marked in watersheds with old and/or stable urban land use, where there are few sources of sediment to replace material scoured by high flows.  There is therefore tremendous variability in the condition of urban streams, depending on historic patterns of development, redistribution of sediments within streams, and hydrogeologic conditions in the watersheds.  However, we suggest that, over time, urban watersheds move towards stable land use, with large amounts of impervious cover and low sediment production leading to stream incision in most locations.

Why important:
Urban stream syndrome alter multiple aspects of stream ecosystem structure and function; from biodiversity to nutrient retention.

For more information:
·         Groffman, P. M., D. J. Bain, L. E. Band, K. T. Belt, G. S. Brush, J. M. Grove, R. V. Pouyat, I. C. Yesilonis, and W. C. Zipperer. 2003. Down by the riverside: urban riparian ecology. Frontiers in Ecology and the Environment 1:315-321.
·         Kaushal, S. S. and K. T. Belt. 2012. The urban watershed continuum:  Evolving spatial and temporal dimensions. Urban Ecosystems 15:409–435.
·         Walsh, C. J., A. H. Roy, J. W. Feminella, P. D. Cottingham, P. M. Groffman, and R. P. Morgan. 2005. The urban stream syndrome: current knowledge and the search for a cure. Journal of the North American Benthological Society 24:706-723.

Contributed by BES Co-PI Dr. Peter Groffman

3 comments:

  1. BETTERMENT FUNDING {bettermentfunding@gmail.com}Hi everyone, i am Alexis Ohanian am so glade coming back to this great forum to testify about the help i received from Chester Brian. I was in desperate need of a loan in other to be free from debt and financial bondage that was place on me by my ex husband. It was really bad that i have to seek for help from Friends,family and even my bank but on one could assist me because my credit score was really bad. So i was browsing with my computer and saw some testimonies from people Chester Brian assisted with a loan, then i decided to contact him on his email {bettermentfunding@gmail.com}, then i received a mail from them and i did all that was asked from me. To my greatest surprise they transferred to my account the loan i requested and now i am so happy clearing my debt and have also started a business with the remaining amount to take care of myself and family. If you need a loan do contact the best loan lender of all time Chester Brian on his email: {bettermentfunding@gmail.com}

    ReplyDelete
  2. God Bless Edward Jones Loans for Helping Me In Time Of Need {Jonesloanfinance@yahoo.com}

    Good Day I am Vanessa Cowen from California and i have a broken up business, until i found this company who help me to gain a loan for business, and now i want to used this short medium to congratulate the company for the fast and safe funds they loan to me without any form of delay, i loan 180,000.00USD from the company at a very low interest rate of 2% to save my business and lots more. i first saw their mail on the internet, everyone always give testimony for what they did, so i quickly contacted them and they all did everything for me without stress and my funds was sent to my account within 24hrs, i was surprise and feel glad, now i now have a standard business control agent who help me, now i will advice those who need urgent loan to contact them now via email : {jonesloanfinance@yahoo.com} OR Text him +1(307) 217-5388..

    ReplyDelete
  3. I'M NOW FULFILL FINANCIALLY BECAUSE OF THE LOAN I GOT FROM UPSTOXFUNDING INC.{ upstoxfunding@yahoo.com }

    I would like to bring this to the notice of the public about how i came in contact with Upstoxfunding INC after i lost my job and being denied loan by my bank and other financial institution due to my credit score. I could not pay my children's fees. I was behind on bills, about to be thrown out of the house due to my inability to pay my rent, It was during this period my kids were taken from me by foster care. Then i set out to seek for funds online where i lost $3,670 that i borrowed from friends which i was rip off by two online loan companies. Until i read about: ( upstoxfunding@yahoo.com ) somewhere on the internet, Still wasn't convince because of what i have been through until a relative of mine who is a clergy also told me about the ongoing loan scheme of Upstox funding at a very low interest rate of 2% and lovely repayment terms without penalty for default of payment. I have no choiIce than to also contact them which i did through text (302) 273-5794That day was the best and greatest day of my life which can never be forgotten when i receive a credit alert of $124,000Usd loan amount i applied for. I utilized the loan effectively to pay up my debts and to start up a business and today i and my kids are so happy and fulfill. You can as well contact them through email: upstoxfunding@yahoo.com OR call or text their helpline: (302) 273-5794. Why am i doing this? I am doing this to save as many that are in need of a loan not to be victim of scams on the internet. Thanks and God bless you all, I'm Wendy Ryan from Arizona, United States.

    ReplyDelete