-
RSS Follow Become a Fan

Recent Posts

Hazardous Waste Segregation
Hydrographic Effects of Urbanization
U.S. to Comply with Global Chemical Labeling by June 1, 2015
The California Diesel Risk Reduction Plan
Another Coastal Devastation for Santa Barbara

Categories

Current Events
Diesel Regulations
Hazardous Waste
Issue of the Month
Stormwater

Archives

June 2015
May 2015

powered by

My Blog

Hydrographic Effects of Urbanization

This article is the first in a series that will provide background on stormwater pollution and mitigation. If you are new to stormwater, I hope these articles will provide some background that can be of use. 

The sheer act of increasing the impervious area in a watershed causes increased runoff volume, increased peak flow and reduced travel time. These impervious surfaces include roads, sidewalks, parking lots, and buildings. Natural flow paths in the watershed are replaced by impervious structures typically associated with development; these include: paved gutters, storm sewers, lined and unlined drainage ditches, and artificial creek and river bedsPrecipitation amount, surface characteristics, such as soil type, vegetative cover and impervious fraction are the primary variables determining the volume of runoff. Travel time is determined by surface roughness, surface slope and the distance of flow. Peak discharge is determined by the interactions between precipitation and travel time. A hypothetical one square mile watershed can be used in conjunction with a hydrographic modeling system (TR-55) to conceptualize the effects of urbanization on flow rate, volume and timing. The figure below shows the rate of runoff versus time for the pre-developed and developed conditions using . Not only is there increased volume of runoff. But it comes faster and earlier than the native state. The increased volume and velocity hydraulically alter any downstream undeveloped portions of the watershed by causing erosion, depositing sediments and altering watershed morphology.

 
The effects of course, do not stop there. Erosion, sediments and changes to watershed morphology degrade habitats. This phenomenon has been studied in detail. In western Washington, an approximate 10 percent change in impervious area in a watershed yields observable loss of aquatic system function. Lower levels of development also cause significant impairment of more sensitive water bodies. Urbanization can be mitigated by retaining runoff from impervious surfaces and either infiltrate them or discharge them at a rate and more like the pre-urbanized state. This is the function of new development standards that include requirements reduce the effects of urbanization on local hydrology.

6 Comments to Hydrographic Effects of Urbanization:

Comments RSS
CapitalHeight on Saturday, April 02, 2016 1:21 AM
Thanks for sharing these info with us! this is a great site. I really like it. Thank you for the site. May God bless you in all your works.
Reply to comment


essay writing services on Wednesday, March 01, 2017 9:27 AM
Hello guys, Now you can get free resources of moviestarplanet game online within minute. You can also hack moviestarplanet online within minute.
Reply to comment


Apexessays on Tuesday, May 02, 2017 11:34 PM
The increased volume and velocity hydraulically increase the alteration of undeveloped portions and proportions.
Reply to comment


wedding chauffeur service on Friday, May 12, 2017 5:27 AM
The setting in the course is worldwide; structures may focus on one of a kind territories and additionally parts, and also they will current cross-provincial examinations alongside mergings.
Reply to comment


order essay on Tuesday, June 06, 2017 9:44 PM
I am new in hydrographic and the information that you share is so wonderful. You give the detail of each part of this topic and I understand everything just in a single article. I have no appropriate word to appreciate you for this article.
Reply to comment


rolex replica on Friday, July 14, 2017 6:30 PM
Thanks for sharing these info with us!
Reply to comment

Add a Comment

Your Name:
Email Address: (Required)
Website:
Comment:
Make your text bigger, bold, italic and more with HTML tags. We'll show you how.
Post Comment