OPEN METHOD
How the planning calculator works
ShambaPump is an early-stage planning tool, not a pump selector. It turns declared farm assumptions into four values that can be checked with a local agronomist, borehole professional and pump supplier.
1. Daily irrigation volume
One millimetre of water over one square metre equals one litre. The calculator converts acres to square metres, multiplies by the selected crop-water depth and divides by the assumed application efficiency. The result is an illustrative gross daily volume, not a fixed agronomic prescription.
Daily litres = irrigated area in m² × assumed mm/day ÷ irrigation efficiency.
2. Target flow
Daily volume is divided by the useful pumping hours entered by the user. Real solar hours, cloud, shading, array temperature and seasonal weather vary. Storage and irrigation zoning can change the required instantaneous flow.
3. Hydraulic and input power
Hydraulic power follows water density, gravity, flow and total pumping head. The interface then applies a broad system-efficiency assumption to show a rough electrical input. It is not a substitute for a manufacturer pump curve at the measured duty point.
4. Solar allowance
The PV value applies an explicit derating allowance and a practical minimum. Controller limits, starting behaviour, cable losses, module temperature, orientation, shading and worst-month irradiation still require an engineered design.
What the estimate deliberately excludes
- borehole or surface-source sustainable yield;
- water quality, filtration and sediment risk;
- detailed pipe friction, pressure surge and electrical protection;
- Kenyan abstraction authorization and site-specific environmental requirements;
- crop-stage scheduling, soil-water storage and effective rainfall;
- supplier warranty, installation quality, spare parts and landed cost.
Evidence standard
Each guide states its assumptions, decision boundary and primary sources. Commercial programme information is dated and does not determine a technical result. Product and regulatory claims must be rechecked before purchase or publication.
Last substantive review: 30 August 2026. Corrections can be sent to editorial@shambapump.com after the mailbox is activated.