This document describes the design, cultural basis, and implementation plan for an integrated aquaponic food production system on the Pugod family land in Ragay, Camarines Sur. The system is designed as a proof-of-concept demonstration model that can be expanded in stages as it proves productive and financially viable.
The system draws water from the river at the farm boundary, passes it through a series of productive stages — fish ponds, grow beds, taro terraces, and prawn channels — and returns it to the river measurably cleaner than it was taken. Every stage produces food. Every stage improves water quality. No mains power is used anywhere in the system.
The design is not foreign to the Philippines. It is a revival of pre-colonial water management and food production practices that Cordillera peoples used for thousands of years before rice displaced taro as the dominant terrace crop. The Hawaiian lo'i kalo system, widely cited as a model for integrated taro cultivation, shares the same ancestral Southeast Asian origin as the flooded terrace systems of the Ifugao, Bontoc, and Kalinga peoples. Bringing this system to Bicol is, in a meaningful sense, a homecoming.
The Pugod land is held as shared family land between the Mulkerrins family and Arianne and Rojan. This is intentional. The enterprise is a family enterprise in the full sense. The late Alejandro — Andy — whose memory this project honours, would have wanted the family working the land together. The shared ownership is a foundation, not a complication.
The land rises steeply from the river — approximately 12 metres of elevation change across the productive area. This gradient, which might appear to be a challenge, is the system's greatest engineering asset. It provides passive gravity-fed flow from the highest point to the lowest without pumping. Only the initial lift from the river to the top of the system requires power.
Before presenting the technical design, it is important to establish that the system described in this document is not an imported or foreign concept being applied to Philippine land. It is a revival of indigenous Filipino water management practice.
Gabi (Colocasia esculenta) has been cultivated in the Philippines for thousands of years. Archaeological and botanical evidence places it in the archipelago before rice. In Bicol, gabi is deeply embedded in food culture — laing, one of the most celebrated Bicolano dishes, is made from gabi leaves. The corm is eaten, the stalks are eaten, the leaves are eaten. Every part of the plant is used. It is not an exotic crop. It is home.
The Ifugao, Bontoc, and Kalinga peoples of the Cordillera developed some of the most sophisticated gravity-fed water management systems in Asia. The Banaue rice terraces — a UNESCO World Heritage Site — are known globally. What is less widely known is that many of these terraces were originally built for taro, not rice. Taro predates rice in the Cordillera as the primary terrace crop.
The hydraulic engineering principles these peoples developed are identical to the system described in this document: cut terraces into the slope, control water flow with earthen bunds, gravity-feed from a higher elevation water source, and allow staged overflow from one terrace to the next. The water management knowledge embedded in this system is Filipino in origin.
The Hawaiian lo'i kalo — the flooded taro paddy — is widely cited as a model of integrated, sustainable taro cultivation. What is not always acknowledged in Western literature is that the Hawaiian system did not originate in Hawaii. Polynesian peoples carried taro cultivation with them across the Pacific from Southeast Asia. The lo'i kalo and the Cordillera flooded taro terrace share the same ancestral origin — separated by thousands of years of geographic divergence but built on the same hydraulic logic.
The practice of raising fish and prawns simultaneously in rice and taro paddies — known in many Philippine communities as palayabab — was widespread across lowland Philippines before monoculture farming displaced it in the twentieth century. Freshwater prawns (ulang, Macrobrachium rosenbergii) living in taro channels, feeding on detritus and algae, cleaning the beds while growing to marketable size — this is not a new idea. It is the restoration of a traditional food system that served Philippine communities for generations.
The system takes water from the river at one point and returns it at another. At every stage between intake and return, the water is used productively and its quality is improved. The full flow path is:
At river intake, the water contains suspended solids, agricultural runoff from upstream properties, and variable dissolved organic matter. The system progressively removes or converts these:
| Stage | Function |
|---|---|
| Swirl filter | Removes suspended solids mechanically — water is physically cleaner after this stage than at intake |
| Sandponic beds | Plant roots in sand media strip dissolved nitrates and phosphates — the primary agricultural pollutants |
| Taro terraces | High-biomass plants absorb remaining nutrients; root systems stabilise soil and prevent erosion |
| Ulang channels | Freshwater prawns consume detritus and algae, converting organic matter into harvestable biomass |
| Polishing pond | Lotus, watercress, and submerged aquatic plants provide a final biological filter |
| Dissolved oxygen | Aerated grow beds and surface agitation raise dissolved oxygen levels — return water is better oxygenated |
No mains power is used anywhere in the system. The power stack consists of three components working together:
| Source | Role |
|---|---|
| Micro-hydro turbine | Installed at the highest-flow point of the river. Continuous 24-hour generation, weather-independent. Baseload power source. |
| Solar array | Roof- or ground-mounted panels provide supplementary daytime generation, topping up the battery bank. |
| Battery bank | Stores generated power for overnight use and provides surge capacity for pump startup loads. |
Powered loads: lift pump, air bubblers in fish ponds, swirl filter flush pumps, bed feed pumps (timed twice daily), transfer pumps between stages, and the rail winch. All low-draw 12V or 24V DC systems wherever possible, minimising conversion losses.
The steep gradient of the Pugod slope — approximately 12 metres of elevation change — makes manual movement of materials up and down the hill impractical at any meaningful production scale. A rail winch system addresses this directly.
Design: Concrete sleeper rail embedded into the slope at consistent grade, cable winch at the top of the hill running off the battery bank, flat-bed trolley capable of carrying harvest crates, feed bags, equipment, and fish transfer containers. The rail doubles as a safety handhold for workers on the steep sections. Electric motor is small, low draw, and locally serviceable.
The full system will be built in stages. The Stage 1 proof of concept is designed to be small enough to build and commission quickly, large enough to demonstrate every principle of the system, and productive enough to cover its operating costs within the first growing season.
| Pond | Capacity |
|---|---|
| Main tilapia pond | 5,000L |
| Stage 1 overflow / taro | 3,000L |
| Stage 2 overflow / taro | 2,500L |
| Stage 3 overflow / taro | 2,000L |
| Stage 4 collection / polish | 2,000L |
The grow beds are housed under shade cloth stretched over a galvanised steel hoop frame. Shade cloth is preferred over greenhouse plastic for Bicol conditions: wind passes through it rather than catching it as a sail, dramatically reducing typhoon risk to the structure.
Media: Coarse river sand. Not a wicking system, not a flood-and-drain system. Water doses into the top of each bed twice daily at calculated volumes per bed and crop type. The bottom of every bed is permanently open. Water drains continuously by gravity into the taro terraces and ulang ponds below. The sand acts simultaneously as a mechanical filter, a biological filter, and a root medium for plant growth.
Initial bed design: IBC (Intermediate Bulk Container) tanks cut in half provide the bed vessels. Cost effective, immediately available, structurally sound, and critically — they can be picked up with a forklift or tractor, emptied, cleaned, and refilled when needed.
Bed dimensions: Two rows per house, each row 1,000mm (40 inches) wide — ensuring every part of the bed is reachable from the aisle without stepping into the media. Bed depth: 400-500mm. House length: 20ft or 40ft modules, aligning with standard container dimensions.
The sandponic media bed system grows a far wider range of crops than raft (deep water culture) aquaponics. Raft systems are limited to leafy crops and some fruiting plants. Sandponics grows all of these plus root vegetables — a significant commercial advantage.
| Category | Crops |
|---|---|
| Leafy crops & herbs | Pechay, mustard greens, lettuce, basil, coriander, Vietnamese mint, lemongrass, kangkong, watercress |
| Fruiting crops | Tomatoes, capsicum, eggplant, cucumber, bitter melon, sitaw (yard-long beans) |
| Root vegetables | Camote (sweet potato), carrots, radish, beetroot |
Below the sandponic grow bed drain, the water enters the taro terrace system. Terraces are cut into the slope in the Hawaiian lo'i kalo tradition — each terrace a shallow flooded pool approximately 150-200mm deep, with a controlled overflow lip flowing to the next terrace below. The water slows at each stage. Nutrients absorbed by taro plants at each level. Erosion at zero.
Gabi varieties: The intention is to source heirloom Bicolano gabi varieties rather than commercial hybrid stock. Multiple varieties exist in the region — some prized for their corms, others for leaf size and quality. Preserving varietal diversity is part of the cultural mandate of this project and aligns with the Slow Food Philippines Ark of Taste programme.
Macrobrachium rosenbergii — ulang — the Philippine giant freshwater prawn — inhabits the channels between taro terrace walls. The traditional practice of raising fish and prawns simultaneously in taro and rice paddies (palayabab) was common across lowland Philippines before monoculture agriculture displaced it.
Nana Bambi's Place includes a dedicated Slow Food and Training Community spoke as one of its twelve operational arms. The Pugod aquaponic and taro system is the living content of that spoke. It is not a demonstration garden separate from commercial operations — it is a fully productive food system that is simultaneously a teaching resource and a cultural archive.
Slow Food Philippines is headquartered in Bacolod City, which is also the Asia Pacific hub for the Slow Food movement. The organisation works specifically on preserving indigenous Filipino food knowledge, heirloom crop varieties, and traditional production methods. Their Ark of Taste programme catalogues traditional Filipino crops under threat of commercial displacement.
This project aligns directly with that mandate. A formal outreach to Slow Food Philippines before construction begins is recommended. They may wish to document the project from day one. The Pugod system could become a registered Slow Food project, providing access to their international network, potential grant funding, and the credibility of their endorsement with the Department of Agriculture.
The approach to the Department of Agriculture is not a permit application. It is an offer of partnership. The department manages water quality concerns across hundreds of farms in Camarines Sur. Most of those farms are degrading local waterways with agricultural runoff, chemical inputs, and unmanaged erosion. This system is the opposite of every problem they deal with.
The formal ask to the Department of Agriculture is designation as a Water Quality Demonstration Site. This is a fundamentally different conversation from applying for a water use permit. A demonstration site designation means:
Before any construction begins, a baseline water quality test is conducted at the river intake point on the farm boundary. Parameters tested: dissolved oxygen, pH, suspended solids, nitrates, phosphates, coliform bacteria, and turbidity. An independent laboratory conducts the test. The results are dated and filed.
Once the system is running, the same parameters are tested at the creek return point on the same date each month. The comparison between intake and return is the evidence. It does not require argument. It is data.
When presenting to the Department of Agriculture, the reference to the Banaue rice terraces is deliberately included. Every Filipino official knows Banaue. It is on the 1000-peso note. It is a UNESCO World Heritage Site. Stating that the water management principles used at Pugod are the same principles developed by the Ifugao people over 2,000 years — and that this project is reviving that tradition in Bicol — changes the nature of the conversation entirely.
This is not a foreign investor building infrastructure on Philippine land. This is a Filipino family reclaiming an indigenous agricultural tradition on land they have held for generations, with the technical knowledge to prove it works and the data to demonstrate it improves the environment.
The build sequence is designed to establish proof at each stage before committing capital to the next. Nothing is built until the stage before it is working.
| Stage | Timing | Action |
|---|---|---|
| 1 | Week 1 | Conduct baseline river water quality test. Document intake point. File results with independent laboratory date stamp. |
| 2 | Weeks 2-4 | Contact Slow Food Philippines. Outline project scope. Request documentation partnership. Identify heirloom gabi varieties for sourcing. |
| 3 | Month 2 | Excavate and form the 5,000L main tilapia pond. High walls, controlled overflow weir, concrete or liner construction. |
| 4 | Month 2-3 | Excavate and form the four staged overflow ponds / taro terraces down the slope. Install overflow lips. Line channels. |
| 5 | Month 3 | Install solar array and battery bank. Install lift pump from river. Commission water flow through the pond system. |
| 6 | Month 3 | Stock tilapia. Begin water parameter monitoring. Allow system to cycle and stabilise — minimum 4 weeks before adding ulang. |
| 7 | Month 4 | Build drain tray as single component with consistent fall. Install IBC half-tanks as first sandponic beds. Erect hoop frame and shade cloth. |
| 8 | Month 4 | Connect grow bed drain to taro terrace inlet. Commission full flow path from tilapia pond to creek return. |
| 9 | Month 4-5 | Plant first crop cycle. Leafy greens and herbs for cafe supply. Trial root vegetables in one dedicated bed. |
| 10 | Month 5 | Introduce ulang into taro terrace channels. Plant heirloom gabi varieties. Begin palayabab integrated system. |
| 11 | Month 6 | Conduct first comparative water quality test at creek return point. Compare against baseline. Prepare data summary for Department of Agriculture. |
| 12 | Month 7 | Invite Department of Agriculture for site visit. Present water quality data. Make formal application for Water Quality Demonstration Site designation. |
The Stage 1 proof of concept is a working system generating food, improving water quality, and demonstrating traditional and modern techniques in integration. From that foundation, every element scales: