Urban Stream Discussion Part 1

I focused on the first set of questions that were directly related to the reading from the discussion led by Ben and myself on urban streams.

As indicated in the reading, why may have previous studies demonstrated that effective impervious area (EIA) is a “better” predictor of stream biological and chemical response than total impervious area (TIA)?

-Effective impervious cover area is impervious cover which is directly connected to a stream. For example, a parking lot that is directly adjacent to a stream. Where as total impervious area includeds all the impervious surfaces such as sidewalks. Therefore, EIA is a stronger indicator for the effects of impervious cover on a stream

2. What is the importance of understanding the historic land cover of an area for predicting current fish assemblages of a stream?

- Understanding the historic land cover of an area is important for predicting the current fish assemblages of a stream because the historic land use could have already degraded the habitat and affect the fish assemblages, such as impoundments could have lead to the populations not being able to be restored to historic population numbers and the introduction of new fish species.

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3. Why might historic land use predict abundance of one fish species but be a poor predictor of another?

-Because the fish that was used in the study, E. scotti, did not show a change in abundance with urban areas as compared to the forested areas.

4. Why might hydrogeomorphic models be a poorer predictor compared to the impervious cover area models for the species used in this study?

- Its not that they are necessarily poor indicators. Often the effective impervious cover influences these indicators as well.

5. Why do you think the species chosen for this study were used as indicator species?

-They are limited in range and are not found abundantly over all. Also, they are fairly sensitive to changes in the geomorphologic processes,

6. What are some indicators of historic land use and how can these be applied to understanding the historic land use?

- Impoundments and reservoirs are fairly good indicators of historic land use.

Developing Sediment Criteria for Water Quality Discussion

During the discussion, I wasn't sure everyone was quite up to speed with the whole SABS framework...so I'm putting up these figures and tables from the paper to try and walk you through the most important points.

We definitely talked about the first figure above. It is the basic framework and main points to follow in the process of developing water quality criteria for suspended and bedded sediments.  The framework is not necessarily limited to sediment criteria...it could be used for any non traditional pollutant that researchers have not been able to test in a laboratory toxicity test setting.

In tables 1 and 2, Cormier et al. go through a hypothetical example to show you how the process might work.  You can see in Table 1 which statistical tests they used and what they intended to learn from the tests. The response indicator they chose was EPT richness.

In table 2, you can see the results of the statistical analysis.  The bottom line (which I circled) is the criteria they chose as their benchmarks for management.  They decided on these numbers for a hypothetical manager trying to protect EPT richness in a mid-Atlantic stream.

Here are some of the questions we went over and how everyone answered:

               What are some ways the authors suggest sediment can affect the biological integrity of waterways?

Low water clarity impairs visibility affecting many animal behaviors such as prey capture, predator avoidance, recognition of reproductive cues, and other behaviors that alter survival.

At very high levels, suspended sediments can cause physical abrasion and clogging of filtration and respiratory organs.

Suspended particles decrease light penetration required for photosynthesis

What are the sources of deposited and bedded sediments? How do human activities increase the rate at which the sediment gets into streams?

Topsoil erosion from land in the watershed

-          Deforestation

-          Agricultural runoff

-          Construction without proper silt fences

Suspended sediment removed from stream banks and from the bed of an upstream channel

-          Channelization

-          Removal of riparian zones

Direct discharge from municipal, industrial and agricultural sources

  

What is the U.S. EPA’s SABS Framework? How does it assist in the development of water quality criteria and restoration targets?

The SABS framework uses a risk assessment approach to estimate effect thresholds for unacceptable levels of SABS in water bodies.

It uses several statistical procedures to compare the estimated effects levels derived from field and laboratory data.

Protective water quality criteria levels are created with scientific evidence to back them up.

  

What were the two levels of protection the team developed for criterion values? Why did they need both? What values did they choose? Were they justified?

ALU: Aquatic Life Uses and MALU: Minimally acceptable aquatic life uses

ALU beneficial in intact ecosystems

MALU beneficial in developed areas which need to set achievable restoration targets.

No more than 7% fines for ALU and no more than 14% fines for MALU

Yes, 7% is justified in that it was deemed protective of the resource and held under the Species Sensitivity Distribution method (most protective precedent). 14% is justified in that it was the mean effect threshold of all methods for MALU.

Urban Stream Discussion Synopsis

My synopsis is the 2nd half of the Urban Streams discussion from Wed, Dec 8th. We broadened our discussion to talk about urban stream restoration in general.

-Someone pointed out that urban stream restoration is a big business and is a good way of employing people. good job security! (assuming, of course, funding sources are reliable)

- We discussed the neccesity of accepting the fact that urban streams are and most likely will always be far from natural, and we can't return to reference conditions

- We talked about the great need to engage urban citizens in the restoration process, and using education of the public to obtain support for restoration activities

- We decided restoration activities should focus on addressing the "urban stream syndrome" before concentrating on in-stream issues: we are not at a place as a society where we can focus on small-scale processes before addressing large issues like flow regime and impervious surface

- We also decided that local ordinances (and possibly fed/state regs) are needed to kick-start folks into using Low Impact Development. The technology is there, we know pervious pavement, rain gardens, green roofs, and rain barrels reduce runoff and increase infiltration, but it is more expensive and there is little incentive for widespread use.

We concluded that for more effective urban restoration, we need an appropriate and reasonable guiding image, and increased knowledge of appropriate techniques and better monitoring.

Ben's Principle

Within stream restorations are only appropriate when the major causes of poor stream quality are identified as in-stream factors. If the flow regime is drastically altered by urbanization, agriculture, or some other changing land use, the driving force behind reduced habitat complexity is likely the change in flow characteristics. Attempting in-stream habitat manipulation will not be a successful strategy in such situations, because it does not fix the problem, and the restoration activities will fail as a result. Most structural changes to in-stream habitat can only be maintained successfully through proper stormwater management (Walsh et al. 2005a), because the degradation to these habitats is a direct result of changing flow regimes. Therefore, in-stream habitat manipulation is a poor use of resources if there are overarching issues with flow regime.

Corey Dunn's Principle

This is an example of ignoring principle 3, which states flow is the primary driver of stream channel physical habitat. While researching interbasin transfers, I came across an example of the drastic economic and potential ecological (if it had been studied) consequences of an interbasin transfer of 88 percent of the flow of the Santee River to the Cooper River for hydropower. The increase in flow in the Cooper River increased the river’s capacity to carry sediment downstream, which was ultimately deposited in the Charleston Harbor. The increased sediment in the harbor had to be constantly dredged to protect shipping lanes inflicting an unforeseen economic cost. To fix this, engineers went full circle and rediverted flow back into the Santee River from downstream sections of the Cooper River (Meador 1994).

Principle and Consequences

Stream habitat is a dynamic system therefore your planning process should be a dynamic process as well (Best Practice)

-Consequences: I chose this as one of my key principles because as a manager it should be your responsibility to view the stream ecosystem as a dynamic system, and if this is not followed using a dynamic planning process then all the efforts that are put into a project could potentially be rendered useless. For example. if a manager were to look at a stream at a certain point in time and were to base all his plans off of this static point in time this could have dramatic outcomes. This point in time could be a low flow or a peak flow, or the use or growing urban area around a stream could be ever changing. If a manager were to place in-stream structures that would be allowable for the low flow, but could not handle the peak flows, they could fail and leave the whole project useless and time wasted.

Stream Restoration: What works? What doesn't?

This is a discussion of the article Roni et al. (2008) "Global review of physical and biological effectiveness of stream habitat rehabilitation techniques".

Note: you can click on any images to enlarge them.

Above are the categories of restoration practices that were documented, the specific techniques involved, the goals of the restoration, and the relative success or factors limiting success. Overall there is the overwhelming need for better monitoring strategy and long term monitoring. It would be very advantegeous to develop monitoring standards so that results from one restoration can be compared to another easily.

SCENARIOS: WHAT WOULD YOU DO IF………
1) Excessive peak flows, as well as normal flows continually undercut steep channel banks, causing large volumes of bank material to enter the stream and lake system.
a. Local Fixes: Reconstruct channel geometry
i. Re-establish floodplain connection
b. Watershed fixes?
i. LID retrofitting
2) Most perennial and intermittent channels have poor streambank integrity and you notice the unusual absence of vegetation.
a. Riparian Vegetation
b. Hydraulic structures
c. Increased floodplain connection
3) Local erosion from concentrated runoff by a large number of paved roads, which are frequently traveled by vehicles.
a. This is a real problem, not sure if you can do anything at all if the roads are commonly used.
4) In a highly urbanized watershed, a stream running through a subdivision frequently floods, risks damage to housing, and has a high sediment load to the lake which it feeds. The stream is severely eroded and houses are situated close to the stream.
a. Instream structures to dissipate energy (reduce sediment load)
b. Watershed fixes
5) Trails caused by livestock, particularly cattle, concentrate runoff into small streams and erodible areas;
a. Fence off livestock
b. Riparian enhancement (slow water velocities)
6) Several watersheds suffer from livestock overuse and improper grazing management systems;
a. Fence off livestock
b. Riparian enhancement
c. Re-structure management systems
7) A stream in an agricultural watershed has exceedingly high nutrient loads. Eutrophication is occuring and is severely impacting biodiversity and aquatic life. You do not know the source of the nutrient pollution.
a. Change farming management strategy?
i. Less use of fertilizer, more controlled management. Offer incentives to farmers to abide by rules.
8) Consider an active meander bend, where the outside of the borders important infrastructure. The river provides habitat to a numerous species of salmon(e.g. Chinook) and trout (e.g. rainbow).

Note: click to enlarge

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