doyle modeling meeting ·...

Simple Models for Stream Restora1on:

Lessons from Back East

Martin Doyle [email protected]

[email protected]

There has been reality check in op2mism about restora2on effec2veness

“There were few significant rela1onships between the fish fauna and physical variables, indica1ng that increasing habitat does not necessarily lead to higher biological diversity.” ; “From this substan2al sample of lowland rivers, there is li

“The project improved mesohabitat structure and fish abundance, and biomass and diversity were greater for 2 years following construc1on. However, the improved fish metrics were in the low range when compared to rural streams in the same ecoregion, and the fish community consisted primarily of tolerant, slow-‐water species. Absent were intolerant and riffle dwelling species, such as insec1vorous cyprinids and darters.” (Schwartz and Herricks, 2007, p 451).

“My sta1s1cal results show that the tradi1onal use of in-‐stream structures for channel restora1on design does not ensure demonstrable benefits for fish communi1es, and their ability to increase fish popula1ons should not be presumed.” (Thompson, 2006, pg 784).

Designing for failure

Lack of modeling around purposes of restora1on -‐ Unrealis1c expecta1ons -‐ Poor loca1on -‐ Poor sizing -‐ Inability to learn from failures

Consider the (not-‐so-‐hypothe1cal) proposed restora1on of Doyle Trib

Proposed to breach small levees, restore riparian vegeta1on, and re-‐meander channel

Goals of project from funding agency and design documents: Improve water quality Improve hydrologic func1on (whatever that might be) Improve stream stability and reduce sediment loading to downstream Improve aqua1c habitat

CORE QUESTION: How would these ac1ons accomplish any of the goals?

Use available informa1on/data and simple quan1fica1ons – models – to assess whether goals are realis1c for a specific project

CONSIDER THE SETTING OF THE PROJECT:

Located on public university lands ~ 1 mile downstream of Wastewater Treatment Plant oukall ~ 1 mile upstream of flood control reservoir

Keeping these goals in mind… Improve water quality Improve hydrologic func1on (flood aHenua1on) Improve hyporheic exchange Improve stream stability and reduce sediment loading to downstream Improve aqua1c habitat

If our last realis1c goal is stabilizing banks and reducing sediment to downstream, then which situa1on is beHer?

(sediment budget of channel restora1on ac1vi1es…); see data in Doyle and Shields, JAWRA for some interes1ng data

Improve hydrologic func1on = Flood peak aHenua1on (?) Modeled using dynamic rou1ng in HEC-‐RAS Modeled pre/post restora1on morphology Range of flood peaks

Over typical lengths of restored streams and standard design

-‐  Reduc1on is at most ~10s of cm

-‐  ~ 2-‐3% reduc1on (not really measurable)

Using basic hydraulic theory (kinema1c wave model) we can predict poten1al maximum benefits of restora1on

Can also show that need ~ 10 miles to have measurable benefits

Lots of hyporheic hysteria (especially in salmon land)

Hester, Poole, Doyle, Limn & Ocean., 2009

Empirical study show there is some effect of restora1on on hyporheic flow

Hester, Poole, Doyle, Limn & Ocean., 2009

Hester & Doyle, WRR, 2009

Using MOD-‐FLOW & HEC-‐RAS

Using MOD-‐FLOW & HEC-‐RAS & Darcy’s equa1on:

Slight increases in background condi1ons can eliminate hyporheic exchange

Hester & Doyle, WRR, 2009

Water quality from stream measurement upstream (publically available data)

P > ~ 0.02 mg/L: P no longer limi1ng (above 0.02 P is saturated; no more uptake)

What about Nitrogen?

Restora1on to improve water quality?

Using basic nutrient spiraling equa1ons (exponen1al decay, Sw, & hydraulics) and ideal condi1ons for stream water quality, restora1on can improve water quality

But, under the real scenario…

Water pollu1on decreases the ability of streams to retain nutrients

Saturated streams cannot efficiently retain N or P, with or without restora1on

Water quality and biota (1) Reference (historic) for 1ll plains streams (Robertson et al. 2006)

(2) EPA recommended surface water quality standard

(1) (2) (3)

(3) Recommended safe concentra1on for sensi1ve taxa (Camargo et al. 2005)

(4) Summer1me concentra1ons in WI streams (Robertson et al. 2006, Stanley& Maxted 2008)

(4) (5)

(5) Concentra1ons at which eggs, fry of some salmonids become affected

(6)

(6) Range of concentra1ons causing 30-‐50% mortality in some amphibians

(7)

(7) EPA drinking water standard

Water quality from stream measurement upstream (publically available data)

P > ~ 0.02 mg/L: P no longer limi1ng (above 0.02 P is saturated; no more uptake)

What about Nitrogen?




SO: line channel with riprap and save money?

Martin Doyle [email protected]

[email protected]

What we can get from simple modeling before complex modeling:

1.  What goals are realis1c? 2.  What goals are realis1c at this specific site? 3.  Is the project large/long enough to poten1ally achieve goals? 4.  How long would it need to be to provide measurable results? 5.  Walk through preliminary model results with funder early in process

6.  Are the realis1cally achievable goals actually desirable?

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