Section 09 · Deep Dives
Hybrids & using the waste
A ram has two outputs: a trickle uphill, and a river of waste downhill. Most designs waste the second to solve the first. This page is about doing better on both counts — pairing rams with other pumps, and spending the spill.
On this page
Ram + solar
The two machines are almost mirror images. A ram delivers all day and all night but only where fall exists; a solar pump delivers only in daylight but runs anywhere the sun reaches. Three arrangements make sense together:
- Seasonal partners: the ram carries the base load through the wet season (when streams run and solar output is worst), and the solar set carries the dry-season peak (when the stream starves but the sun shines). One storage tank, two complementary energy sources, and either can be sized for the average rather than the worst case.
- Parallel into one tank: where demand exceeds what either alone delivers, both feed the same storage. The ram's constant 24 h trickle plus the solar set's midday surge flattens the combined curve nicely — and the tank only has to bridge the gaps, per tank sizing.
- Duty separation: the ram supplies the household and livestock water it handles so well (Applications), while the solar set runs an irrigation block with a completely different demand shape. No storage gymnastics required.
A solar set with battery storage mimics the ram's day-round output — at a capital cost and with a five-to-ten-year battery replacement cycle the ram never sees. Where fall exists, the ram is usually the cheaper way to buy the night hours; the honest question is what the batteries cost per delivered cubic metre over their full life, per the ten-year arithmetic.
Ram + micro-hydro
Where a site has both fall and demand for electricity, the same water can be asked to do two jobs. A micro-hydro turbine takes the head first and returns the water to the channel; a ram takes it lower down. They compete for the same resource, so the design questions are:
- Who gets the dry-season flow? A turbine can throttle to a trickle; a ram needs its minimum drive flow to cycle (typical capacities). In practice the hydro plant claims the scarce months and the ram is stopped or throttled — a ram abandoned dry suffers no harm (Installation).
- Cascade the head, don't split it. Turbine at the top of the fall, ram below the tailrace: each machine sees clean, undivided head, and the total abstraction conversation with the regulator happens once (Permits).
- Don't run a ram off a turbine tailrace surge unless the tailrace level is genuinely constant — rams read water level, not nameplates. A small forebay between the two smooths it (Intakes).
Spending the waste stream
The waste is not dirty — it is the same clean water that entered the drive pipe, minus the delivered share. It leaves with energy and arrives continuously. Designs that capture it treat the ram as a two-product machine:
- Irrigation below the ram: the classic win. A gravity channel or buried line from the outfall serves a garden or fodder plot at zero additional energy — the ram's "inefficiency" waters the field. In a cascade this is exactly the recovery principle from Cascades, applied to plants instead of a second pump.
- Aquaculture: the waste flow keeps a fish pond exchanged and oxygenated; the pond, in turn, is a settlement lagoon for the silt the intake missed, and its overflow can drive a second ram or irrigate. Philippine village schemes combine rams and ponds routinely.
- Recharge & storage: lead the waste to a pond or dug reservoir below the ram and it becomes a header source for a second use, or simply an infiltration basin recharging the ground that feeds your spring.
- Micro-power: a tiny overshot wheel or pico-turbine on the outfall will light a pump house or charge a fence — worthwhile as demonstration, marginal as economics, honest about scale.
- Do no harm: whatever spends the waste, the outfall still needs to clear the foundation (mounting), still needs to resist ice dams in winter (cold climates), and still owes the stream its environmental flow per Permits — the delivered share is what leaves the catchment, and the waste arrangements must return the rest.
The waste stream is the ram's largest output. Designing as though it didn't exist is the most common planning mistake on otherwise good sites — and the easiest one to fix with a channel, a valve and a paddock.