LEC275 Catchment hydrology

© Nick Chappell, Oct 2020 LEC275 Lecture 1 – Catchment Hydrology

Global threats

Introduction LEC275 Lecture 1 – Catchment Hydrology

Flooding

Deadliest natural disasters

1st 1931 floods of Huang He (Yellow), Yangtze & Hai 1,000,000-2,500,000 2nd 1887 Huang He (Yellow) flood 900,000-2,000,000 3rd 1556 Shaanxi earthquake: 830,000

Introduction LEC275 Lecture 1 – Catchment Hydrology

Flooding

Even considering climate change

‘...the impacts on people will be felt mainly through water, driven by shifts in regional weather patterns, particularly rainfall and extreme events...’ (Stern, 2007 p13)

Introduction LEC275 Lecture 1 – Catchment Hydrology

Poor water quality

As water quality deteriorates within developing countries

Water supply development not keeping pace to reduce poor access to safe drinking water in many countries (WHO, 1998 data) Introduction LEC275 Lecture 1 – Catchment Hydrology

Solutions

Quantify & mitigate at catchment-scale

Introduction LEC275 Lecture 1 – Catchment Hydrology

Module objectives

To introduce concepts, plus measurement and analytical techniques used by professional hydrologists to solve water-related problems in catchments (notably flood forecasting/mitigation and water quality remediation)

outcomes

1/ quantitative description of catchment hydrological processes 2/ use data and basic models to derive solutions 3/ assimilate primary literature to address wider problems, plus understand current data & theoretical limitations

Introduction LEC275 Lecture 1 – Catchment Hydrology

Lecture outline

L1 Introduction to catchment hydrology L2 Rainfall: processes & measurement L3 Rainfall: analysis L4 Evaporation: direct measurement L5 Evaporation: processes L6 Subsurface water: states and flows L7 Runoff: measurement & basic analysis L8 Rainfall-runoff: processes & pathways L9 Rainfall-runoff: basic modelling L10 Rainfall-runoff: distributed modelling L11 Water quality: measurement L12 Water quality: treatment

L15 Research case studies

Introduction LEC275 Lecture 1 – Catchment Hydrology

Module reading resources

Class text Shaw, E.M., Beven, K.J., Chappell, N.A., and Lamb, R., 2010. Hydrology in Practice. Fourth Edition. CRC Press / Taylor and Francis, . ISBN: 9780415370424 £44.99 CRC Press

Introduction LEC275 Lecture 1 – Catchment Hydrology

Module reading resources

Library [DRH classmark]

plus PDF files via Moodle

https://modules.lancaster.ac.uk

or dedicated LEC.275 website

Introduction LEC275 Lecture 1 – Catchment Hydrology

http:// www.es.lancs.ac.uk/people/nickc/n210.htm Introduction LEC275 Lecture 1 – Catchment Hydrology

Practicals

Practical 1 Field hydrology measurements week 3 and 4

Introduction LEC275 Lecture 1 – Catchment Hydrology

The catchment

Introduction LEC275 Lecture 1 – Catchment Hydrology

Definition of a drainage basin

= catchment = watershed (US-only)

General: Area of land draining to a river

Precise: Area of land draining through a river gauging station

Introduction LEC275 Lecture 1 – Catchment Hydrology

1/ Experimental Catchments:

processes researched at 0.1 – 10 (100) km2

2/ Catchments gauged by national or state agencies:

Wales (20,761 km2) = 161 nested gauged basins: med 87 (av 244, 0.6-4010) km2 > 15 per 2000 km2 Marsh and Hannaford (2008) UK Hydrometric register. CEH Wallingford

State within a tropical country (Sabah state 73,371 km2 in Malaysia) = 40 nested (rated) gauged Basins: med 750 (av 2458, 11-12300) km2 1 per 2000 km2 Was formerly listed on: http://www.did.sabah.gov.my/index.php?q=hydrologysurvey

Introduction LEC275 Lecture 1 – Catchment Hydrology

Case Study Basin: Segama on Borneo

Why ?

1/ Global perspective

2/ Show issues similar

3/ Show hydrological approach the same

Introduction LEC275 Lecture 1 – Catchment Hydrology

~ size of

Introduction LEC275 Lecture 1 – Catchment Hydrology

DID-Sabah river gauging stations

Introduction LEC275 Lecture 1 – Catchment Hydrology

2450 km2 Segama Catchment gauged by DID-Sabah (721 km2 Ulu Segama station)

Leong (1974) The geology and mineral resources of the upper Segama valley and Darvel Bay area, Sabah, Malaysia. Geological Survey of Malaysia, p16 Introduction LEC275 Lecture 1 – Catchment Hydrology

2450 km2 Segama Catchment gauged by DID-Sabah (721 km2 Ulu Segama station)

Leong (1974) The geology and mineral resources of the upper Segama valley and Darvel Bay area, Sabah, Malaysia. Geological Survey of Malaysia, p16 Introduction LEC275 Lecture 1 – Catchment Hydrology

DID gauging site at Limkabong, Sabah (eg Greer et al. 1996 IAHS Publ 236 p453-461) Introduction LEC275 Lecture 1 – Catchment Hydrology

DID gauging building at Limkabong, Sabah Introduction LEC275 Lecture 1 – Catchment Hydrology

2450 km2 Segama Catchment gauged by DID-Sabah (721 km2 Ulu Segama station)

Leong (1974) The geology and mineral resources of the upper Segama valley and Darvel Bay area, Sabah, Malaysia. Geological Survey of Malaysia, p16 Introduction LEC275 Lecture 1 – Catchment Hydrology

721 km2 Ulu Segama station

Introduction LEC275 Lecture 1 – Catchment Hydrology

contains...

Danum Experimental Catchments (< 2 km2)

Introduction LEC275 Lecture 1 – Catchment Hydrology

Video clip of the upper Segama catchment near Danum Valley Field Centre Introduction LEC275 Lecture 1 – Catchment Hydrology

Why study hydrology at the ‘catchment scale’?

Generic issues:

1/ Flood forecasting & mitigation

2/ River water quality problems (quantifying and solving)

Introduction LEC275 Lecture 1 – Catchment Hydrology as in UK LEC270: River Caldew in Mosedale e.g. Eden catchment

The 147.2 km2 basin was continuously gauged at Holm Hill until 10/2/2000. Now gauged by EA further upstream at Sebergham and downstream at Cummersdale

SEPA 2007 Solway Tweed River Basin Management Plan (SEPA 2015 update) Introduction LEC275 Lecture 1 – Catchment Hydrology as in UK LEC270: River Caldew in Mosedale e.g. Eden catchment

The 147.2 km2 basin was continuously gauged at Holm Hill until 10/2/2000. Now gauged by EA further upstream at Sebergham and downstream at Cummersdale

SEPA 2007 Solway Tweed River Basin Management Plan (SEPA 2015 update) Introduction LEC275 Lecture 1 – Catchment Hydrology as in UK e.g. Eden catchment

Storm Desmond flood (5-6 Dec 15)

SEPA 2007 Solway Tweed River www.edenriverstrust.org.uk Basin Management Plan River Eden & Tributaries SSSI (SEPA 2015 update) Introduction LEC275 Lecture 1 – Catchment Hydrology

NERC Q-NFM as in UK www.lancaster.ac.uk/lec/sites/qnfm e.g. Eden catchment

Modelling effectiveness of natural flood management SEPA 2007 Solway Tweed River Basin Management Plan (SEPA 2015 update) Introduction LEC275 Lecture 1 – Catchment Hydrology as in UK e.g. Eden catchment

Quantifying NFM benefits on farmland SEPA 2007 Solway Tweed River Basin Management Plan (SEPA 2015 update) Introduction LEC275 Lecture 1 – Catchment Hydrology equally e.g. Lune catchment

Introduction LEC275 Lecture 1 – Catchment Hydrology equally e.g. Lune catchment

Abstractions for Public Water Supply (PWS)

So water quality critical

Introduction LEC275 Lecture 1 – Catchment Hydrology Storm Desmond floods in Carlisle, Eden catchment (Dec 2015)

Practical options linked to these catchment issues

1/ Field measurements of fundamental catchment properties (Ou basin, Lune tributary) - used in 2020-21

2/ Field-trip on using natural processes in natural flood management (Lune catchment) - not used in 2020-21

Tree planting to help mitigate floods (Sprint tributary, Kent Catchment) Introduction LEC275 Lecture 1 – Catchment Hydrology

1/ Flood forecasting

Introduction LEC275 Lecture 1 – Catchment Hydrology

2/ River water quality problems (quantifying and solving)

turbid Segama in flood (at Ulu Segama gauging station) Introduction LEC275 Lecture 1 – Catchment Hydrology

2/ River water quality problems (quantifying and solving)

due to commercial logging upstream Introduction LEC275 Lecture 1 – Catchment Hydrology

2/ River water quality problems (quantifying and solving)

abstraction station on Segama for Public Water Supply Introduction LEC275 Lecture 1 – Catchment Hydrology

2/ River water quality problems (quantifying and solving)

Raw water treatment works (WTW) on Segama for PWS (Lahad Datu town) Introduction LEC275 Lecture 1 – Catchment Hydrology

What basin hydrological characteristics do we need to know (to solve)?

1/ How much rainfall? (climate-driven system) 2/ How much evaporation? - affect P input & water resource availability - affect antecedent moisture status – flood peak 3/ What is the internal-state (inside basin)? - antecedent moisture status – affect flood peak - residence time in ground – affect river WQ - catchment pathways – affect river WQ a) hydrological characteristics of soil, regolith, rock b) way water moves on & within slopes

4/ How much runoff? (catchment-integrated response)

Introduction LEC275 Lecture 1 – Catchment Hydrology

Catchment characteristics moderate input characteristics / forcing to affect output

What are they…?

Introduction LEC275 Lecture 1 – Catchment Hydrology

Illustrate… UK Flood Estimation Handbook

improvement by Kjedsen et al. (2008) EA/Defra Science Rpt SC050050 see Shaw et al. (2010) p322-326

Introduction LEC275 Lecture 1 – Catchment Hydrology

1. Contributory Area

Introduction LEC275 Lecture 1 – Catchment Hydrology

2. Soil, regolith & rock type (~ storage)

Introduction LEC275 Lecture 1 – Catchment Hydrology

3. Lakes / reservoirs (~ storage)

Introduction LEC275 Lecture 1 – Catchment Hydrology

4. Rainfall

Introduction LEC275 Lecture 1 – Catchment Hydrology

Segama catchment characteristics moderate input characteristics / forcing to affect output

Introduction LEC275 Lecture 1 – Catchment Hydrology

1. Contributory area

2450 km2

721 km2

adapted from Leong (1974) p16 Introduction LEC275 Lecture 1 – Catchment Hydrology

2a. Solid geology and regolith (‘drift geology’; C)

Leong (1974) p32 Introduction LEC275 Lecture 1 – Catchment Hydrology

…presence of deep aquifer storage?

sediment aquifer (but downstream)

rock aquifer

Leong (1974) p338 Introduction LEC275 Lecture 1 – Catchment Hydrology

…presence of deep aquifer storage?

Chappell et al. 2007 Chapter 1. Forest environments in the Mekong river basin. Springer, Tokyo

Introduction LEC275 Lecture 1 – Catchment Hydrology

…presence of deep aquifer storage?

northern Borneo only

Chappell et al. 2007 Chapter 1. Forest environments in the Mekong river basin. Springer, Tokyo

Introduction LEC275 Lecture 1 – Catchment Hydrology

2b. Soil type

Acrisol-Alisol

Introduction LEC275 Lecture 1 – Catchment Hydrology

2b. Soil type

Chappell et al. 2007 Chapter 1. Forest environments in the Mekong river basin. Springer, Tokyo Introduction LEC275 Lecture 1 – Catchment Hydrology

Acrisol-Alisol soils

storage reduces with depth

Sherlock (1997) p162, PhD

Introduction LEC275 Lecture 1 – Catchment Hydrology

3. Presence of lake / reservoir storage?

LDWS Sepagaya dam

Introduction LEC275 Lecture 1 – Catchment Hydrology

4. Rainfall regime key factor affecting which catchment characteristics important

e.g., in tropics – areas with tropical cyclonic rainfall versus areas without

Bidin & Chappell (2006) Hydrol. Process., 20: 3835-3850 Introduction LEC275 Lecture 1 – Catchment Hydrology

Rainfall regime

e.g., areas with tropical cyclonic rainfall – lots of SOF Queensland (South Johnstone, March ’85) Introduction LEC275 Lecture 1 – Catchment Hydrology

First stage of hydrological characterization Catchment water budget

INPUT (flow)

Change in catchment storage / t

OUTPUT (flow)

Introduction LEC275 Lecture 1 – Catchment Hydrology

First stage of hydrological characterization Catchment water budget

INPUT I (flow)

Change in catchment dS / dt storage / t

OUTPUT O (flow)

Introduction LEC275 Lecture 1 – Catchment Hydrology

First stage of hydrological characterization Catchment water budget

INPUT I m3/s (flow)

Change in catchment dS / dt m3 / s storage / t

OUTPUT O m3/s (flow)

Introduction LEC275 Lecture 1 – Catchment Hydrology

First stage of hydrological characterization Catchment water budget

dS / dt = I – O

I = O + dS / dt

Introduction LEC275 Lecture 1 – Catchment Hydrology

First stage of hydrological characterization Catchment water budget

dS / dt = I – O

I = O + dS / dt

P = (Q + Et) + dS / dt

Introduction LEC275 Lecture 1 – Catchment Hydrology

First stage of hydrological characterization Catchment water budget

dS / dt = I – O

I = O + dS / dt

P = (Q + Et) + dS / dt m3/s = m3/s + m3/s + m3 / s

or divide by catchment area (m2) x 0.2778

mm/hr = mm/hr + mm/hr + mm/hr

Introduction LEC275 Lecture 1 – Catchment Hydrology

strictly

P = (Q + Et) + dS / dt + G

G = catchment leakage subsurface flow crossing the catchment divide ~ not returning to the channel before reaching the river gauging station

Introduction LEC275 Lecture 1 – Catchment Hydrology

G = catchment leakage

Particularly issue for micro-basins (e.g., < 0.1 km2)

or small basins on rock aquifers e.g., 1.0 km2 SST Low Hall basin in Eden (Ockenden et al. 2014 Hydrol Res 45: 200-212)

Introduction LEC275 Lecture 1 – Catchment Hydrology

L1 Reading

Gregory, K.J., and Walling, D.E. 1974. Chapter 2: Drainage basin characteristics. In Drainage basin form and process. Arnold, London. [PDF; DRI(G) in library] Kirby, C., Newson M.D., and Gilman, K. 1991. Plynlimon research: the first two decades. IH report 109. Institute of Hydrology, Wallingford. [PDF; DRHej(K)] ’s catchment-based approach for improving water quality https://www.gov.uk/government/publications/catchment-based-approach-improving- the-quality-of-our-water-environment

Introduction LEC275 Lecture 1 – Catchment Hydrology

Example test/exam questions

1/ Which four catchment characteristics are used within the UK Flood Estimation Handbook (Kjedsen et al., 2008) to calculate peak flow in a UK river: A Rainfall; a term for lake/reservoir storage; a term for soil, regolith & rock; contributory area

2/ Define the water balance equation for a catchment:

A P = (Q + Et) + dS / dt + G

Introduction