Recent Erosion and Deposition Processes

PHASE 1 EROSION STUDY 2 Recent Erosion and Deposition Processes

Presented By

SEAN BENNETT, Ph.D.

University at Buffalo

Study 2 Leader

West Valley Demonstration Project

Quarterly Public Meeting

November 15, 2017

Define the goals of the Study 2 and the tasks assigned

Present the methodologies employed and the results obtained

Summarize the broader implications

OUTLINE

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TASKS: Quantify environmental parameters that would reduce the predictive uncertainties in future erosion using a landscape evolution model

STUDY 2 -Recent Erosion and Deposition Processes

Task 2.1b: Digital Mapping of Potential Analogue Sites (Gullies)

Report completed July 2, 2016

Task 2.1b: Digital Mapping of Potential Analogue Sites, Amendment 1 – Expanded Study of 2010 and 2015 LiDAR Data

Report completed October 18, 2017

Task 2.2: Quantify Infiltration Capacity

Task 2.5: Quantify Erodibility of Cohesive Sediment

Task 2.6: Quantify Erodibility of Clastic Sediment

Combined report completed March 1, 2017

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TASK 2.1b: Digital Mapping of Potential Analogue Sites (Gullies)


Objectives: Using the 2010 LiDAR dataset, (1) define the morphologic characteristics of gullies at the WVDP, and (2) identify analogue gullies nearby using the same data and methodologies

Methods: Using LiDAR data and GIS techniques, topographic information from the gullies were determined including slope, length, orientation, width, depths, and cross-sections

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TASK 2.1b: Digital Mapping of Potential Analogue Sites


Gully 1 (NP-1)

Relative Distance (m)

0 20 40 60 80 100 120 140 160

Ele

va

tio

n (

m)

1280

1300

1320

1340

1360

1380


0 20 40 60 80 100 120 140 160

Gu

lly D

ime

nsio

n (

m)

0

20

40

60 Width

Depth

width: 0.653

depth: 0.489

Gully 1 (NP-1)


1 10 100 1000

Gu

lly D

ime

nsio

n (

m)

1

10

100

Width

Depth width: 0.842

depth: 0.718

Gully 1 (NP-1)

average slope: 0.578

average inner slope: 0.491

Inner Gully Outer Gully




0 10 20 30 40 50 60 70

Ele

vation (

m)

1320

1330

1340

1350

1360

1370

1380

Upstream

Midstream

Downstream

Gully 1 (NP-1)

Typical gully at the WVDP (Gully 1, NP-1) Plateau

Gully

Inner Gully

Outer Gully

Mouth ofInner Gully

Outer Gully Drainage Divide

Inner Gully Drainage Divide

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TASK 2.1b: Digital Mapping of Potential Analogue Sites (Gullies)


Areas Investigated Gullies 1 and 2 in Area 5, underlain by the Lavery Till, were morphologically similar to the gullies at the WVDP

Gully 2, Area 5

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TASK 2.1b: Expanded Study of 2010 and 2015 LiDAR Data


Objectives: To determine geomorphic changes in topography using the 2010 and 2015 LiDAR datasets, focusing on: (1) gullies, and (2) bed elevation for selected stream channels

Methods: Morphologic analysis of gullies on the WVDP (13), and analogue gullies located within the WNYNSC (Areas 5 and 6)

Spatially-averaged parameters (length, slope, width, depth)

At-a-point changes (elevation, width, depth)

Longitudinal profiles of stream channels: Buttermilk, Franks, Quarry, Heinz, and Gooseneck Creeks

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Results: Similar to values reported in the FEIS (lower advance rates)

Spatially-averaged rates

Length: 0.1±2.7%/yr

Slope: -0.6±1.5%/yr

Width (near head): 2.9±6.4%/yr

Depth near head: 2.9±7.9%/yr

Average rates at-a-point

Width: 0.028±0.042 m/ha-yr

Depth: 0.002±0.014 m/ha-yr

Slope: -0.006±0.012 m/ha-yr

Ele

va

tio

n (

m)

390

395

400

405

410

415

420

20102015

Wid

th (

m)

0

20

40

60


0 20 40 60 80 100 120 140

De

pth

(m

)

0

5

10

15

20

Gully 1


0 20 40 60 80 100 120 140

Diffe

ren

ce

(m

)

-20

-10

0

10

20 ElevationWidthDepth


0 10 20 30 40 50 60


0 10 20 30 40 50 60

Midstream Downstream


0 10 20 30 40 50 60

Ele

va

tio

n (

m)

400

405

410

415

420

425

430

20102015

Upstream

Inner gully Outer gully

Inner gully Outer gully

(a) (b)

(c) (d)

(e) (f) (g)

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Results: Buttermilk, Franks, Heinz, and Gooseneck Creeks display a net increase (aggradation) in bed elevation with time (Heinz Creek: 0.003±0.009 m/km2-yr)

Quarry Creek shows a net decrease (incision) in bed elevation with time, -0.005±0.009 m/km2-yr

Changes conditioned by geospatial uncertainties and hydrologic and geomorphic variability during the study period

Bed E

levation (

m)

360

380

400

420

River Kilometer (km)

0 1 2 3

Change in B

ed

Ele

vation (

m)

-2

-1

0

1

2

Bed E

levation (

m)

360

380

400

420

Franks Creek2010

Franks Creek2015


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TASK 2.2: Quantify Infiltration Capacity


Objectives: Field activities sought to quantify infiltration rate for selected surficial geological materials (in particular, the Lavery Till) using a double ring infiltrometer

Methods: A standard double ring infiltrometer (ASTM D-3385) consisting of two steel rings was used

37 tests performed in trenches dug in support of Study 1

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TASK 2.2: Quantify Infiltration Capacity


Results: Similar to the values used in the FEIS

Spatial average:

33±59 mm/hr

20.98±37.8 m3/yr

Average by elevation (shown)

Average by frequency (for the tills):

2±2 mm/hr

1.33±1.37 m3/yr

Infiltration Rate (mm/hr)

0.1 1 10 100

Ele

va

tio

n (

ft)

1100

1200

1300

1400

Spatial Average (all data)Average by ElevationAverage by Frequency

Infiltration Rate (m3/yr)

0.1 1 10 100

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TASK 2.5: Quantify Erodibility of Cohesive Sediment


Objectives: Field activities sought to quantify the erodibility of selected surficial geological materials (in particular, the Lavery Till) using the jet erosion test (JET)

Methods: The JET forces water to impinge the material’s surface forming a scour hole, and the rate of erosion can be used to estimate the material’s critical shear stress tc and erodibility coefficient kd

37 tests performed in trenches dug in support of Study 1

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TASK 2.5: Quantify Erodibility of Cohesive Sediment


Results: Similar to values used in the FEIS

Spatial average:

tc = 42.7±16.4 Pa

kd = 2.05±1.75 cm3/N-s

Average by elevation (shown)

Average by frequency (for the tills):

tc = 41.7±7.6 Pa

kd = 1.76±1.20 cm3/N-s

c (Pa)

20 40 60 80 100

Ele

va

tio

n (

ft)

1100

1200

1300

1400

Spatial Average (all data)Average by ElevationAverage by Frequency

kd (cm

3/N-s)

0 2 4 6

13 Scour depth method

TASK 2.6: Quantify Erodibility of Clastic Sediment


Objectives: Field activities sought to quantify the surface grain size statistics of selected stream channels near the WVDP

Methods: Wolman (1954) pebble count method, and grain size percentiles determined: D10, D16, D50, D84, D90, and D95

A total of 49 pebble counts were conducted in and near the WNYNSC along streams as well as Cattaraugus Creek

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Results: Similar to values used in the FEIS

No spatial variation in sediment texture was observed along streams

Excluding a few statistical outliers, grain size data can be aggregated:

D10 = 11 mm D16 = 17 mm

D50 = 47 mm D84 = 117 mm

D90 = 154 mm D95 = 225 mm

TASK 2.6: Quantify Erodibility of Clastic Sediment

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Analogue gullies can be used for a variety of purposes (site visits, analysis of landscape evolution, and field-based monitoring programs)

Observations of gully erosion, infiltration rate, erodibility of glacial materials, and stream bed grain size distributions agree well with previous work and are aligned with those analyses presented in the FEIS (2010)

These newly collected data will further constrain the input parameters required to numerically simulate landscape evolution at the WVDP and to reduce the predictive uncertainty of future erosion at the site

Broader Implications

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QUESTIONS?

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Recent Erosion and Deposition Processes

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