Exploring the relationship between water availability and small-scale

agricultural systems near Mount Kenya

Drew Gower; Advisor: Dr. Kelly CaylorDepartment of Civil & Environmental Engineering,

Princeton University

Nanyuki Catchment

MRC

Hydrologic Variability

Source: Weismann et al., 2000

Irrigated Agriculture

• Hydrologic variability offset by irrigation using river water

• Supports a range of operations from export-driven large farms to household gardens producing food for domestic consumption.

• Large farms draw water from the rivers through separate irrigation systems and are buffered by boreholes and reservoirs

• Households receive water for irrigation and domestic use through community water projects

Source: Aeshbacher et al., 2005

Source: Gichuki, 2004

Climate Change Impacts

Source: USGS, 2010

Research Questions

• What is the current and past distribution of dry season irrigation use in the Nanyuki Catchment?

• What populations are currently most dependent on irrigation use for their livelihoods?

• How might climate change affect water availability and livelihoods in the Nanyuki Catchment?

• What factors affect the resilience of dryland agricultural systems generally?

Previous Work• Conducted weekly flow

measurements in 10 to 20 households in 25 projects

• Consisted of recording the amount of time needed for water to fill an 18 liter bucket

• Lasted between 5 and 6 months, depending on the project

• Also recorded amount and type of water use at one household per project

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 170

10

20

30

40

50

60

70Fl

ow R

ate

(lite

rs/m

inut

e)

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 160

10

20

30

40

50

60

70

Flow

Rat

e (li

ters

/min

ute) Kaga Water Project

Maka Water Project

Source: Paul McCord (Personal Communication)

Week

Household and Manager Surveys

• More than 1,050 household-level surveys on water use, agricultural practices, cropping strategies, and demographic information

• Eighty water project-level manager surveys on rule formation, water rotation strategies, and water project infrastructure

Ongoing Work• Weekly stream gauging and

isotopic sampling at 10 locations in the Nanyuki Catchment

• Weekly collection of natural and agricultural vegetation samples for isotopic analysis

• Helping projects to upgrade their master meters to collect project-level flow information

Current Gauge Station

Proposed Gauge Station

MRC

Socio-hydrologic Model

Hydrologic Model

Crop Model

Agent-Based Model

• Composed of a conceptual hydrologic model, an agent-based model and a crop model

• Validated with hydrologic measurements and distribution of agricultural yields

• Used to investigate socio-hydrologic outcomes of climate and land use change

• Outcomes evaluated by total crop yield and fraction of users above a minimum threshold of water availability

AcknowledgementsThis research was supported by the National Science Foundation, Grant No. 1115009. I’d also like to thank the following people for their advice and assistance:• Dr. Kelly Caylor (Princeton University)• Sally Goodman (Princeton University)• Eliza Harkins (Princeton University)• John Gitonga (Mpala Research Center)• Dr. Tom Evans (Indiana University)• Paul McCord (Indiana University• Dr. Jampel Dell’Angelo (Indiana University)• Mengistu Seketedi (Lewa Wildlife Conservancy)• Linden McBride (Cornell University)

Questions?