# Presentation: 359841

## Effects of Whole-River Fertilization on Benthic Macroinvertebrates: Feeding a Starving River.

- Gary Lester, EcoAnalysts, Inc.
- Charlie Holderman, Kootenai Tribe of Idaho,     Project Lead

- NEAEB 2008
- Bartlett, New Hampshire

## Overview of Presentation

- Background regarding Kootenai River
- Nutrient enhancement experiment on the river
- Preliminary responses to fertilization

## Slide 3

## Libby Dam

## 		Libby Dam

- 		**Libby Dam**
- Construction initiated in 1968
- Dam was dedicated by President Ford in August 1975
- Lake Koocanusa is 90 miles long (40 miles in Canada)
- Reservoir is 370 feet deep
- Dam provides power, flood control, and recreation

## Dam acts as a sediment transport barrier

**Dam acts as a sediment transport barrier**
**Reservoir acts as a nutrient sink**
**Dam operations result in an unnatural hydrograph**
**Floodplain wetlands disconnected by dikes and flood control**

## THE PHOSPHORUS STORY

## Total Phosphorus - 2003

## RESULT: Trophic collapse due to“cultural oligotrophication” 

- Collapse of native fish populations including:
- Kootenai River white sturgeon (endangered)
- Burbot
- Westlope cutthroat trout
- Rainbow trout
- Kokanee

## Trout Comparisons

**Trout Comparisons**

## The Study

- A large-scale, controlled nutrient enhancement experiment is underway to stimulate productivity in the Kootenai River.

## Cooperators - IKERT

- _I_nternational _K_ootenai _E_cosystem _R_estoration _T_eam
- Kootenai Tribe of Idaho
- Idaho Fish and Game
- Bonneville Power Administration
- BC Ministry of Environment
- Montana Fish Wildlife and Parks
- Academics and consultants
- USACE

## MONITORING

**KR1**

**MONITORING**
**SITES**

**Treatment**

## Monitoring Parameters

- Nutrients
- TDP, SRP, TN, NH4, NO2+NO3
- Primary Productivity
- ChlA, Periphyton and phytoplankton community structure
- Secondary Productivity
- Invertebrate abundance, biomass, community structure
- Tertiary Productivity
- Fish abundance/biomass, community structure, condition

## Study Design

- Monthly sample for water quality, periphyton and invertebrates from April – October
- Replicates (1-6) collected at each site for various parameters
- Fish population work once per year
- Five years of pre-treatment data (completed)
- Five years of post-treatment data (started 2005)

## Nutrient Augmentation

- Addition of P (NH4P2O5) toward a target level of 1.5ug/L in river in 2005, 3.0 in 2006/2007/2008
- Target 20:1 N/P ratio in the river
- Summer 2005 flow rate of 0.31L/min
- Flow rate is dependent upon river discharge
- 2km mixing zone

## Slide 17

## Slide 18

## Slide 19

## Sampling Methods - Periphyton

- Artificial substrates (30 day colonization times) for ChlA
- Scrape and filter known area
- Samples monthly at most sites
- One composite sample from natural substrate (3 cobble scrape) for taxonomy

## Control – KR10

- Test – KR 9.1

## Sampling Methods – Invertebrates

- Quantitative benthic samples using a modified slack sampler, 0.25m2 area
- Sample events in spring, summer and fall (when flows allow)
- Six replicates per site
- Full sorts by KTOI staff using 3x lens
- ID to genus/species, worms to class, by EcoAnalysts
- Whole-sample dry weight and dry weight by order (Eco)

## Modified slack sampler

- Dimensions = .5m x.5m
- 500 micron mesh net
- Allows sampling of large substrates

## Slide 24

## RESULTS

## Effect of P Additions on TP, SRP Concentration  (Hoyle 2006)

**Effect of P Additions on TP, SRP Concentration  (Hoyle 2006)**

- Total Phosphorus

- Soluble Reactive Phosphorus

- Sites are 1km apart.

- Treatment

- Treatment

## Nitrate & Ammonia Concentrations(Hoyle, 2006) 

- Nitrite-Nitrate

- Ammonia

- Treatment

- Treatment

## Chlorophyll Response, Kootenai River (Hoyle 2006) 

- Treatment

## Treatment

- ???

## Treatment

- ???

## Treatment

## Hydropsychidae

**Hydropsychidae**

- Ephemerella inermis/infrequens

- Orthocladius sp.
- Simulium sp.

- SPRING

- SPRING

- SPRING

- FALL

- FALL

- FALL

## Treatment

## SPRING

- FALL

- FALL

- FALL

## Slide 35

## Slide 36

## Slide 37

## E. inermis/infrequens

- highly dominant

- Treatment

- Treatment

- Treatment

- Treatment

## Fisheries

## Slide 40

## Slide 41

## Slide 42

## SUMMARY

- Saw immediate increase in primary productivity (ChlA) to 30km downstream
- Increase in macoinvertebrate density and biomass immediately below treatment; lesser response further downstream
- No significant alteration of macroinvertebrate community structure – getting more of the same bugs
- Starting to see response in fish diet– expecting (hoping) to see increase condition factor/numbers soon

## Acknowledgements

- Charles Holderman, KTOI
- Ryan Hardy, IDFG
- BPA - funding