Principle and Consequences Tim

Monitoring successes and failures need to be shared among agencies and researchers to aid others in nation-wide and world-wide stream rehabilitation efforts.

If practitioners fail to heed this principle, it could be detrimental to the entire field of stream habitat management.  Without researchers having access to past successes and failures they are forced into conducting their own research on the project (which might not be practical) or using a technique involving trial and error.  Having sound evidence to base practices and techniques on, give the manager(s) peace of mind moving forward with the project.They can also justify their management decisions with stakeholders.

Principle and Consequences

Principle
Streams progress toward a state of dynamic equilibrium, where they balance discharge, sediment transport, and slope. BAS: Lane’s Balance.

Ignoring this principle will surely result in problems when designing channels. For example, in an urban stream with higher velocities, just because we rebuild the channel doesn’t mean we can ignore the discharges frequent to the channel. Designing a bed with a sediment size that is too small will cause the channel to erode and for fines to be washed downstream. Broadly defined, ignoring Lane’s balance can 1) make the channel unstable and 2) decrease water quality (increased sediment load). These two factors can make the stream unhabitable to ecology.

Key Principles example and consequences

Research is a critical element of the process, pre-restoration data helps show change, and data collection continued on reinforces if the project worked properly and could help future projects.

Consequences:

There is no way to tell if the restoration worked or not unless there is research. Pre-restoration gives a baseline for the condition of the stream in question and any change from there is theoretically from the restoration itself. If a management project is implemented and there is no post data, there is no way to tell if anything happened at all. This is bad for the project itself and confidence in stakeholders as well as for future projects that could benefit from knowing what failed and what was successful.

New River expedition on NPR

Thought some folks might enjoy to hear about the New River and a local advocacy group dedicated to the New.

http://www.wvtf.org/news_and_notes/ee.php

Management Implications of spatial and ecosystem thinking

Topic: Management implications of spatial and ecosystem thinking

Readings: Wiplfi and Baxter 2010

Fausch et al. 2002

Summary of readings

Fausch et al. 2002

-This paper addresses the importance of viewing streams as continuous, hierarchical, heterogeneous, and linear. It emphasizes that streams contain a mosaic of different types of habitat that are utilized by different species and lifestages through time.

-Historically research was conducted at the reach scale; however, advances in technology and a better understanding of fish movement requires us to look at habitat at larger spatial scales. For example, the presence of an adult trout in one reach might have more to do with its ability to find suitable habitat in other areas of the stream or ocean (rearing habitat) as it ages and moves (corridors) rather than the physical characteristics of that reach.

-The suggested new approach for research and conservation

1. Research must be conducted at appropriate scales for the questions of interest.

2. The importance of different physical and ecological processes will be revealed at

different spatiotemporal scales, and processes will interact.

(The availability of habitat is driven by processes at different spatial scales, which all

must meet the requirements for a species to persist)

3. Rare or unique features in a riverscape, either in space or time, can have overriding

effects on stream fishes.

(ex. a beaver pond may provide habitat (source) for different species that migrate to

other parts of the stream (sink) or a fire that occurs rarely may deposit wood in the

stream that affects the overall stream community).

4. unintended consequences of habitat degradation will occur in all directions, including

upstream. (fish move upstream and downstream and are affected by disturbance

throughout the habitat they encounter)

5. Fisheries ecologists who study stream fishes must strive to make observations and test

predictions at the scale at which managers effect change.

Overall research and management must address problems at the appropriate scale, which is often larger than a stream reach.

Wipfli and Baxter 2010

-This paper also underscores the importance of maintaining connectivity among the entire stream but focuses on energy requirements rather than the physical characteristics of the stream.

-Depending on where you are in the river continuum the fauna receive food (energy and nutrients) from somewhere else in the stream.

-examples-Local primary and secondary production may be subsidized by…..

-Tributaries– even food from small fishless streams is washed downstream.

-Terrestrial– riparian inputs such as leaves and terrestrial insects

-Marine – Migrating fishes from the sea

-These imputs vary by season and often life histories are synchronized with the availability of said inputs.

-Overall it is easy to focus on the physical habitat within a stream, but the amount of energy in a system may also limit the presence and abundance of stream fish. These imputs come from areas other than the focal area, which highlights the importance of both terrestrial and stream connectivity to a system.

Most relevant discussion questions

1. At what spatial and temporal scales do most habitat studies occur and at what scales do most natural processes and human effects occur?

2. What is meant by the intermediate habitat scale and what makes it so tough to study at this scale?

3. Is the intermediate habitat scale the same for all species?

4. How might downstream events affect upstream community assemblages?

5. What restoration challenges occur at larger spatial scales?

Thinking about habitat patchiness and connectivity at multiple spatial scales can get confusing, but overall the class seemed to comprehend the material.

Streamflow Alteration In Class Discussion (Dec. 1st)

(Image reference)



Link to journal article of the week (must be sign into VT library)
http://www.esajournals.org.ezproxy.lib.vt.edu:8080/doi/pdf/10.1890/100053

“Alteration of streamflow magnitudes and potential ecological consequences: a multiregional assessment.” (Carlisle et al. 2010)

1. What were the ecological consequences of altered streamflow magnitudes, as quantified in this article?

a. (Physical alteration) streamflow magnitudes à altered versus nonaltered. Minimum and Maximum flows inflated or diminished.

b. (Ecological consequences) Fish and Macroinvertebrate communities. Impaired versus non-impaired. Ratio of observed taxa to expected taxa (reference) within region.

2. What happens to biological communities within the altered streams in comparison to reference streams?

a. Nest-guarders replacing simple nesters (can provide oxygen/flow to eggs)

b. Active swimmers replacing benthic and streamlined forms

c. Increased macroinvertebrate taxa with the ability to exit stream

d. Pool-loving taxa, fine-grain substrate loving-taxa

e. Invasion

f. PROBLEM with this article….where are the numbers for abundance data of organisms?

3. What are a few of the physical responses, to alterations in streamflow magnitude, which lead to these ecological consequences?

a. Floods of varying size and timing are needed to maintain a diversity of riparian plant species and aquatic habitat.

b. Reduced magnitude and frequencyà

i. Deposition of fines into gravel (no high flows to remove and transport fine sediments that fill interstitial spaces in productive gravel habitats)

ii. Channel stabilization and narrowing

iii. No import of, habitat providing, woody debris

iv. Floodplain disconnection (floodplains can be important for some species reproductive success-nursery grounds, no high flows to bring in organic matter from floodplain, high flows onto floodplain required for some riparian vegetation success)

v. Vegetation encroachment

c. Increased magnitude and frequencyà

i. Bank erosion and channel widening, bed scouring

ii. Streams that dry temporally, generally in arid regions, have aquatic and riparian species with special behavior or physiological adaptations that suit them to harsh conditions of drought.

d. Flow stabilization

i. Invasion or establishment of exotic species leading to local extinctions, threat to native commercial species and altering biological communities

4. What about the floodplain biological communities? What would diminished flow magnitudes do?

a. Inuadation of floodplain required for some riparian vegetation success

b. Vegetative encroachment into channel

c. Modification of riparian communities by causing plant mortality, reduced growth, competitive exclusion, ineffective seed dispersal or establishment.

5. So what if magnitude is not altered? What about the other four flow components? Are they important and if so, how?

a. IN ADDITION: What about changing magnitude WITHOUT a Dam?

i. This can occur in urban areas. Low flows become elevated in urban areas because waste water enters and increases/elevates baseflows and increases nutrients in water.

ii. ORà from agriculture withdrawls and groundwater pumping

b. Frequency

i. Extreme daily variations below peaking power hydroelectric dams = harsh environment, frequent disturbance. Mortality of aquatic populations suffering from physiological stress,

c. Timing

i. Some species use seasonal flow conditions as CUE to reproduce (Life history traits)

ii. Riparian plant species with specific germination timing (cottonwoods, needs flow peaks to occur before germination period)

d. Duration

i. Change in floodplain inundation, independent of changes in annual volume of flow, can alter the abundance of plant cover types

ii. Loss of riffle habitat with prolonged inundation

e. Rate of change

i. Washout and stranding of aquatic species

6. How could we conduct a study to include the other four components? Would inclusion of these dimensions increase or decrease the severity and likelihood of stream impairment?

a. Use annual hydrographs (timing, duration, rate of change, frequency)

b. Increase

7. What are the issues between arid and wet climate areas?

a. Differences in water management in watersheds

b. Aridà use for agriculture/irrigation/drinking wateràyou get DIMINISHED max and min flows

c. Wetà dams for flood control (you get more elevated MINIMUM flows and unaltered MAX flows)

d. Western US water issues, water rights out west, who owns what issue?

e. Conserving differences between the West and East

f. Desalination of ocean water is too cost and energy expensive

8. How do you balance human needs with ecological requirements?

a. Public educationà current public opinion is concerned with QUALITY and not QUANTITY

b. Policy changes

c. Improved water resource management, instream flow water management, better science

d. Water is a FINITE resource

e. People don’t understand what is going on, need to educate the publicà they drive policy maker decisions.

f. Need a basic government commitment to promise to provide water to the people for basic needs, government protection of aquatic ecosystems

g. Technological improvements! Improve consumption of water, distribution of in-home water plumbing, water reuse

What Went Wrong at Cochiti Dam

Numerous studies have been conducted on the Cochiti Dam in New Mexico in order to quantify the changes in stream geomorphology following dam construction in 1973. The dam, one of the largest in the United States, was constructed primarily for sediment and flood control of the Rio Grande River and is a good example of what happens when Lane's diagram (one of my key principles) is not followed.

Following construction, there was little effort to restore natural flows and sediment was trapped upstream of the dam. Consequently, the once braided stream channel transformed into a single channel system with an increasing depth, decreasing width, and islands eroded away. Average sediment size has increased from fine sands to gravels.

The above graph (Richard and Julien 2003) shows peak flows (purple bars), sediment flowing into the study reach (dotted line), and sediment flowing out of the study reach (solid line) following dam construction.

Cross-sectional profiles from 1971-1998 as taken by Richard and Julien (2003).

Aerial photos depicting changes in stream channel morphology after dam construction (Richard et al. 2005)

Ecologically, these changes have been problematic for the Rio Grande silvery minnow because habitat has been heavily degraded. In addition, because the river is no longer connected to the floodplain, lack of regular inundation has decreased the population of cottonwood while increasing the invasion of nonnative species such as saltcedar and Russian olive.




Richard, G. A., and P. Y. Julien. 2003. Dam impacts and restoration of an alluvial river- Rio Grande, New Mexico. International Journal of Sediment Research 18: 89-96.
Richard, G. A., P. Y. Julien, and D. C. Baird. 2005. Case study: modeling the later mobility of the Rio Grande beow Cochiti Dam, New Mexico. Journal of Hydraulic Engineering 131: 931-941.