Rural Water - Quarter 1, 2009 - (Page 31)

DAILY Discharge, cubic feet per second the stream. During particularly dry years, these events can events, dramatically increasing erosion rates. This reduces result in signiﬁcant ﬁ sh kills within a stream. Fall brings the the amount of available habitat by eroding the logs, boulreturn of lower temperatures, generally increased river ﬂows ders and gravel. Further, the increased f low rates directly and larger quantities of leaf material to the streams (Figure 1). impact many stream organisms, especially in streams that The large amount of leaf material can have signiﬁcant effects lack natural cover such as the above mentioned logs and on water chemistry in streams and also lead to problems with boulders. clogging at water treatment plant intakes. Seasonal changes in rivers are the result many different While the seasonal events described are fairly predictable, changes that occur during the year. To review these changes rivers regularly change in a short amount of time. Flow rates as we see them here in Kentucky, let’s start in the middle of can increase dramatically in only a few hours (Figure 3). Along winter. In a typical year, ﬂows will be relatively high because with the increase in ﬂow come increases in turbidity and an rainfall is higher, there is little evaporation due to the cold increased potential for pollutants to get to a water treatment temperatures and plants have not started growing yet. The plant intake. Figures 2 and 3 not only show the changes that heavier rains and high river ﬂows lead to increased erosion both within the river channel and in the surrounding watershed, causing the turbidity within the river to increase dramatically. During this same time, due to USGS O3314500 BARREN RIVER AT BOWLING GREEN, KY the colder temperatures and the rapidly 20000 moving water, dissolved oxygen levels are 10000 at their highest. It is also at this time that many water treatment plants experience problems with debris building up around their intakes. As winter progresses into spring, the rains continue as do the high ﬂows. Air and water temperatures start to 1000 rise, plants begin to grow and consume water and algae growth within the streams increases. As spring progresses, trees leaf out and shade many small streams, keeping them relatively cool even though air 100 temperatures are slowly climbing Jan 01 Feb 01 Mar 01 Apr 01 May 01 Jun 01 Jul 01 Aug 01 Sep 01 Oct 01 Nov 01 Dec 01 2006 2006 2006 2006 2006 2006 2006 2006 2006 2006 2006 2006 Summer ushers in what are typically –––– Median daily statistic (35 years) –––– Estimated daily mean discharge lower rainfall amounts and much higher –––– Daily mean discharge –––– Period of approved data temperatures, resulting in lower overall stream ﬂows. Water temperatures rise, especially in streams that have little or no tree cover (this is very common in agricultural areas), which reduces the dissolved oxygen USGS O3314500 BARREN RIVER AT BOWLING GREEN, KY levels. In addition to high temperatures, 10000 streams with little or no tree cover usually experience excessive algae growth (Figure 2). So much algae can grow that ﬁ sh popu1000 lations are dramatically impacted as it can over-grow and take over suitable habitat Eventually the algal growth dies off and begins to decay, dramatically increasing 100 the biological oxygen demand within the stream. This further reduces the already -lowered dissolved oxygen levels within DAILY Discharge, cubic feet per second Figure 3. Flow data from the Barren River at Bowling Green, Ky. Note how flow rates can change in a matter of days or even hours. Also note the very low flows during the summer of 2007 compared to those during the summer of 2006. 10 Jan 01 Feb 01 Mar 01 Apr 01 May 01 Jun 01 Jul 01 Aug 01 Sep 01 Oct 01 Nov 01 Dec 01 Jan 01 2007 2007 2007 2007 2007 2007 2007 2007 2007 2007 2007 2007 2008 –––– Median daily statistic (35 years) –––– Period of approved data –––– Daily mean discharge –––– Period of provisional data –––– Estimated daily mean discharge First Quarter 20 9 3 First Quarter 2009 • 31 i uarte 2009 re

Table of Contents Feed for the Digital Edition of Rural Water - Quarter 1, 2009

Rural Water - Quarter 1, 2009 Contents From the President Question & Answer: Water Conservation in the Home Avoiding the Humpty Dumpty Approach to Data Backup From the CEO What the Future Holds Asset Management for Small Communities Understanding Your Surface Water Source: The Rivers Hydraulic Models Expeditionary Water Packaging System Graces Delta The Rural Water Rally in April Training in Hawaii Regulatory Update Rural Water Releases Report on Water Infrastructure Projects and Economic Stimulus Legislation Throwing My Loop Advertisers.com Index to Advertisers

Rural Water - Quarter 1, 2009

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