Connectivity of River Flow

Marisa HendronLimnology 475/575

Presented November 25, 2009Prof. Mark Sytsma

Flow Characteristics

Figure from Alley et al., 2002, Science

•Vertical• Nutrient Cycling

•Longitudinal• Navigation

•Lateral•Floodplain Interaction

The Hyporheos• Defined by saturated sediments experiencing

flow surrounding riverbed

- Nitrification- High Phosphate Concentration- Oxidation of Methane, Sulfides- Respiration, turnover of OC- Contains dissolved O from surface water

-Denitrification, Ammoniafication- Reduction of sulfate- Methanogenesis- Low Dissolved Oxygen- High Silica Concentration

Flow & River Health

• Natural flow develops heterogeneous patches and supports biodiversity

• Upwelling aerates fish eggs in sediment• Groundwater is loaded with bio-available solutes• Longitudinal flow regulates transport of sediment and organic matter

http://www.treehugger.com/salmon-snake-river-photo.jpg

Flow, Hyporheic Ecology & Lake Nutrients• Function of hyporheos influences amount and

type of nutrients that reach lakes

http://waterontheweb.org/under/lakeecology/06_watershed.html

•Chemical processes in rivers differ greatly between low and high flow periods

Disturbances in Flow

Richter, et al. Restoring Environmental Flow by Modifying Dam Operations, Figures 1 & 3

Above: Green River, KentuckyRight: San Joaquin River, California

Consequences of Flow Disturbance

• Reduction of natural flood cycles reduces biodiversity long-term

•Natural geomorphological processes are diminished

•Nutrient cycles are disrupted

Restoration EffortsCase Study: Merced River, CA

• Initial restoration did not account for three dimensional flow dynamics

• Flow variation across time is important for shaping river morphology and species composition

http://merced.stillwatersci.com/pdf/6/vol1/Figures.pdf

Conclusions

• Maintenance of all dimensions of flow in lotic systems is important for proper nutrient cycling and biological function.• Riverine ecology will affect the quality of water and nutrients received by lentic systems within the watershed.• Connectivity is a key dimension of river flow and

should be emphasized in the development of restoration plans.

Bibliography• Hendricks, Susan. Microbial ecology of the hyporheic zone: a perspective

integrating hydrology and biology. The North American Benthological Society, Vol 12, No. 1 (Mar., 1993), pp. 70-78.

• Howard, K. W. F. et al. Ground-Surface Water Interactions and the Role of the Hyporheic Zone in Groundwater and Ecosystems. Ed. Alper Baba et al. Nato Science Series, Vol. 70, 2005.

• Kondolf, Mathias G. et al. Process-Based Ecological River Restoration: Visualizing Three-Dimensional Connectivity and Dynamic Vectors to Recover Lost Linkages. 2006. Ecology and Society Vol. 11, No. 2.

• Nilsson, Christer and Birgitta Malm Renofalt. Linking Flow Regime and Water Quality in Rivers: A Challenge to Adaptive Catchmetn Management. 2008. Ecology and Society, Vol 13, No. 2, pp. 18-38.

• Richter, Brian D. and Gregory A. Thomas. Restoring Environmental Flows by Modifying Dam Operations. 2007. Ecology and Society Vol. 12, No. 1, pp. 12.

• Stanford, Jack and J. V. Ward. An Ecosystem Perspective of Alluvial Rivers: Connectivity and the Hyporheic Corridor. The North American Benthological Society, Vol. 12, No. 1 (Mar., 1993), pp. 48-60.

• Thomaz, Sidinei et al. Floods increase similarity among aquatic habitats in river-floodplain systems. Hyperbiologia (2007) 579: 1-13.

• Thorp, James H. et al. The Riverine Ecosystem Synthesis. Elsevier Inc, 2008.