Flooding and the Ecology of Streams

265 views
215 views

Published on

Extreme weather is becoming more common in our region. Flood events can impact human health and safety, and result in substantial costs to property and infrastructure. Geared toward municipal decision makers and concerned citizens, this forum provides on-the-ground examples of flood resilience strategies that can help Hudson Valley communities minimize risks while conserving financial resources.

Presentation by Dr. Stuart Findlay, Aquatic Ecologist, Cary Institute for a flood management forum hosted by the Cary Institute of Ecosystem Studies in Millbrook, NY on May 4, 2013.

0 Comments
1 Like
Statistics
Notes
  • Be the first to comment

No Downloads
Views
Total views
265
On SlideShare
0
From Embeds
0
Number of Embeds
1
Actions
Shares
0
Downloads
2
Comments
0
Likes
1
Embeds 0
No embeds

No notes for slide

Flooding and the Ecology of Streams

  1. 1. Flooding Effects on Stream EcologyStuart FindlayFINDLAYS@CARYINSTITUTE.ORG
  2. 2. OUTLINE• Floods are “normal” for streams and rivers• Physical effects and their legacies (long)• Connection to floodplains and watersheds• Consequences for organisms
  3. 3. Streams have long life-spans• Roughly 10,000years sinceglaciation – a localstream may haveexperienced ahundred 100-yrfloods
  4. 4. GloballyLow, declining or regulated flow more of an issueColorado River Delta. Nat GeographicTopping et al 2003Nilsson et al 2005, Science
  5. 5. Locally – Increased Flows• Wappinger Creek0501001502002503003504004505001920 1940 1960 1980 2000 2020Discharge(cfs)• HudsonAnnualSummer
  6. 6. Wappinger Creek at Red Oaks Mill0 50 100 150 200 250 300 350 400 450 500Mean Annual Flow (CFS)0510152025No.ofobs.Mean Q 1st 25 yrs(240 cfs)Mean Q last 25 yrs(292 cfs)
  7. 7. Causes of higher flow• More precipitation and/or intensity• Vegetation• Land-use, particularly impervious cover– Affects peak, timing and infiltrationFLOWTIMEUrbanForestedRain
  8. 8. Physical Legacies of High FlowsThe channel
  9. 9. Real life looks more complicated
  10. 10. Physical Legacies of High FlowsWood
  11. 11. Logs are re-distributed by floods
  12. 12. Floods increase connection to surroundings• Floodplains –– Active movement of animals
  13. 13. • Floodplains –– Transport of debrisFloods increase connection to surroundings
  14. 14. • More strongly connected to more of the watershedFloods increase connection to surroundingsDRYWETDRYWET
  15. 15. Chloride as an exampleRain event March 11-15, 201320253035404550556065700 24 48 72 96 120 144 168 192 216 240 264 288 312 336 360 384 408 432 456 480Stream DepthChloride (mg/L)
  16. 16. Consequences for Biota -A Tough place to live sometimes
  17. 17. Stream AlgaeSycamore Creek, AZMarti et al., 1997Valett et al. 1994
  18. 18. BugsMcMullen and Lytle 2012MayfliesDipteraCaddisfliesStoneflies
  19. 19. SUMMARY/RE-CAP• Flooding will happen – plan for (more of) it• Flooding sets the physical template• Flooding is not ecologically harmful in the long run– Floodplain/watershed connections– Biota have evolved under these conditions

×