HYDRAULIC HABITAT MODELING AND TIME SERIES ANALYSIS FOR GILA RIVER FISH SPECIES

Presentation to Interstate Stream Commission By: Thomas Payne, Normandeau Associates

November 10, 2014

GOAL OF THE STUDY

• SWCA and Normandeau were contracted by ISC to quantify ecological impacts of AWSA flow alterations on key species.

• Normandeau tasks: – Hydraulic habitat modeling – Habitat suitability criteria (HSC) development – Habitat time series analysis

HYDRAULIC HABITAT MODELING

• Starts with surveys of river cross-sections • Hydraulic models are built from the data • Calibrated models simulate:

– Water depth – Water velocity – Substrate and/or cover

• Models predict hydraulic variables over a range of flows

(also known as PHABSIM, RHABSIM, RHYHABSIM, etc.)

HYDRAULIC HABITAT MODELING

• Predicted hydraulic variables are linked with Habitat Suitability Criteria (HSC)

• HSC indicate the suitability of the hydraulic variables as aquatic habitat

• Each hydraulic variable is assessed for suitability at any specified flow

• The suitability of each variable is linked and weighted to create a net index called Area Weighted Suitability (AWS)

XSEC 1

XSEC 2 Hydraulic Model

Velocity: v i

Depth: d i

Substrate: s i

Biological Model

Velocity

Cv

Sv i Sd i Ss i Substrate

Cs

Area Weighted Suitability (Or Weighted Usable Area)

Flow

AW

S

HYDRAULIC HABITAT MODELING

GEOMORPHOLOGY STUDY

Study Site Location map

HABITAT SUITABILITY CRITERIA Observational data modified by professional judgment

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Mean Column Velocity (fps)

Spikedace Spawning

Interim FINAL SD spwn

BOR '88 SD spwn

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Depth (ft)

Interim FINAL SD spwn

BOR '88 SD spwn

Barber '70 SD spwn

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sand/silt gravel cobble rubble boulder small veg lrg veg

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Substrate/Cover Type

Interim FINAL SD spwn

SPECIES OF INTEREST

Fish

Native

Spikedace (E)

Loach Minnow (E)

Gila Chub (E)

Desert Sucker

Sonora Sucker

Longfin Dace

Non-native

Green Sunfish

Smallmouth Bass

Channel Catfish

Common Carp

Red Shiner

Birds

Native

Southwest Willow

Flycatcher (E)

Reptiles

Native

Northern Mexican

Garter Snake

Narrow-headed Garter

Snake

Amphibians

Native

Chiricahua Leopard Frog

(T)

Non-native

Bullfrog

Crustaceans

Non-native

Crayfish

x x x x

HSC developed

x HSC not developed

AREA WEIGHTED SUITABILITY Habitat Index Functions vs. Flow for TNC and Birds Study Sites

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Flow (cfs)

Reach Habitat : TNC_Xsecs_MAsub

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Loach Minnow AdultSpikedace AdultDesert Sucker AdultSonora Sucker AdultLongfin Dace Juv/AdultChub spp Juv/Adult

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Flow (cfs)

Reach Habitat : Birds_Xsecs_MAsub

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Loach Minnow AdultSpikedace AdultDesert Sucker AdultSonora Sucker AdultLongfin Dace Juv/AdultChub spp Juv/Adult

HABITAT TIME SERIES

• Typically starts with daily flow values • Converts each daily flow to its equivalent AWS

index • Sorts and graphs the converted AWS index by

magnitude • Quantifies AWS habitat index change with flow

over time • Allows comparison of flow scenario effects on

fish habitat

HABITAT TIME SERIES ALTERNATIVES Comparing two alternative flow regimes with habitat duration

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Percent Exceedance

TNC- Desert Sucker Spawning (Feb - April)

Historic

CUFA

FLOW SCENARIOS EVALUATED

Quantify fish habitat change for: 1. Historical flow after AWSA diversions for TNC &

Birds sites: i. without climate change ii. with climate change of 8% overall flow reduction

2. Historical flow after AWSA diversions minus Upper Gila and Ft. West ditch flows with environmental flow augmentation for TNC site:

i. without climate change ii. with a climate change of 10% overall flow reduction

GILA RIVER HABITAT DURATION Area under the curve for TNC Reach

Historic CUFA % Diff. Historic CUFA % Diff. H Loach Minnow

Spawning 1210 1243 2.8 1216 1251 2.8Loach Minnow

Larvae 923 931 0.8 951 959 0.9Loach Minnow

Juvenile 3270 3321 1.6 3239 3291 1.6Loach Minnow

Adult 1987 2016 1.5 1944 1972 1.5Spikedace Spawning 1059 1077 1.7 1076 1096 1.9Spikedace Larvae ⁄Fry 568 571 0.5 585 588 0.5

Spikedace Juvenile 2410 2444 1.4 2413 2448 1.5Spikedace Adult 3360 3422 1.9 3331 3396 1.9

Desert Sucker Spawning 6496 6383 -1.8 6350 6231 -1.9

Sonora Sucker Spawning 5556 5497 -1.1 5389 5328 -1.1

Sucker spp Larvae 439 442 0.6 450 453 0.7Desert Sucker

Juvenile 3000 3040 1.3 2960 3000 1.3

ea U de t e Cu e a ues o G TNC Reach

Without Climate Change With Climate Change

MAJOR RESULTS

• Natives: – Loach Minnow: 0.8% to 3.2 % increase in all life stages

habitat – Spikedace: 0.3% to 1.9% increase in all life stages habitat – Chub spp: up to 2.3% reduction in larval habitat – Sucker spp: up to 2% reduction in spawning habitat – Longfin Dace: up to 2.7% reduction in spawning habitat

• Non-natives: – Smallmouth Bass: up to 2.5% increase in spawning habitat – Common Carp: up to 5.0% decrease in spawning habitat

Scenario 1

• AWS of natives tend to peak at a much lower flow than those of the predators.

• 10 cfs chosen as environmental flow.

• Natives: 0.3% to 9.0% habitat increase

• Non-natives: 0 to 10.7% habitat increase

MAJOR RESULTS Scenario 2

CONCLUSIONS

• 11 fish species were evaluated in this study (6 natives, 5 non-natives) – Habitat analysis for species other than fish is

generally not compatible with this method. – This method does not address the very complex

ecological functions (competition, predation, food availability) for and between species.

• Up to ±5% habitat change for natives and non-natives in their various life stages

• Releasing 10 cfs back to the river: up to 11% habitat increase for all species

Population Viability Analysis of Spikedace and Loach Minnow

Bill Pine, PhD working with

November 2014

Goals of the Study

• ISC hired SWCA/Dr. Bill Pine to: – Develop a preliminary Population Viability

Analysis (PVA) for loach minnow and spikedace

– Estimate extinction probability of key species using PVA

November 2014

Spikedace and Loach Minnow • Federally protected –

Endangered • Small, benthic fish species • Endemic to Gila River basin • Populations have declined

due to habitat changes and negative effects of invasive species

• Short lived - spikedace ~ 2 years loach minnow ~3 years

November 2014

Loach minnow Gila River near Gila, NM 090612 R.C. Helbeck

Spikedace

Simulation scenarios

November 2014

Scenario Purpose Assumption/key trait Female fish count

Long-term carrying capacity

1 Viability of small populations

Based on best info + Variability in survival

20-100 NA

2 Resilience and recovery

Based on best info + Variability in survival

20 500

3a Low recruitment for 5 years due to drought, then 45 years normal conditions

Based on best info + Variability in survival Flow-fish survival relationship

400 400

3b Persistent low recruitment due to non-native predataors

Based on best info + Variability in survival High predation on native fish by nonnative predators

400 400

November 2014

As an example if variability in survival is reduced then extinction risk declines, here shifting from the red to the blue line for a given age-1+ female fish abundance

At the same time as abundance of age-1+ female fish increases the extinction risk goes down across a wide range of juvenile survival rates

Resilience (Scenario 2)

• Scenario designed to assess recovery time for very small populations (~20 adult females)

• Similar to what may happen if downstream populations “seeded” from upstream

• Designed to mimic natural variation in survival that likely occurs

November 2014

November 2014

Starting with 20 female fish in one of 200 populations. Annual survival in this simulation is highly variable sigma = 0.8

Spikedace Resilience Sigma= 0.8

October 2014

After 10 years these 200 populations have diverged with some having more than 500 individuals and some with < 50.The dotted arrows show the range in possible population sizes across the color spectrum.

Spikedace Resilience Sigma= 0.8

October 2014

After 10 years most populations are here in the red and orange colors, so it is estimated that about 50% of the populations would have increased to 200-300 individuals

Spikedace Resilience Sigma= 0.8

October 2014

Results

November 2014

Scenario Purpose Extinction risk Take home message

1 Examine viability of small populations

High (65-98%) over 500 years for very small populations and high variation in survival Low for larger populations or low survival variation

Populations > 100 females robust

2 Resilience and recovery

Very small over 50 years in a source-sink framework

Rapid recovery potential

3a Low recruitment for 5 years due to drought, then 45 years normal conditions

1.5 % (loach minnow) 8% (spike dace) – occurs during low recruitment Zero if low recruitment does not occur and mortality normal

Resilient to short-term low recruitment (5 years)

3b Persistent low recruitment due to non-native predators

High extinction risk (100% both species) in less than 10 years if low recruitment persists

Be wary of non-native predator expansion

November 2014

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Flow (cfs)

Reach Habitat : TNC_Xsecs_MAsub

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Loach Minnow Larvae/FrySpikedace Larvae/FrySucker spp LarvaeChub spp LarvaeChannel Catfish AdultSmallmouth Bass Adult

• “Sweet spot” are flows that benefit natives but do not promote non-native species (e.g. Catfish & Bass)

• As an example ~20-40 CFS may promote natives but limit non-natives (based on PHABSIM outputs)

Conclusion

• Flow augmentation must be carefully considered – May reduce risk of habitat fragmentation – Could increase risk of non-native expansion potentially

reducing native fish survival (and increasing extinction risk)

• Robust monitoring efforts and surveys should be undertaken to track fish community response to any flow augmentations.

• Linking “flow models” with the “fish models” will help to make better management decisions in the Gila River to benefit native fish species.

November 2014

Thank you!

• Questions?

November 2014