Water Sequestration Ponds in Farm 03
Three (3) water sequestration ponds (see Red Arrows in Fig. 01) are proposed for Cadu Farm 03 -- a main water sequestration pond and two smaller rainwater sequestration ponds.
First draft of the conceptual design. The proposed location of the three (3) water sequestration ponds in Farm 03 have been guided by the existing terrains, vegetation and permanent crops, as well as existing and planned uses of Cadu Farm 03 as an EcoCulture food production system. Further, the conceptual design of the EcoCulture proposed projects in Cadu Farm 03 considered its being an integral part of a larger EcoCulture development consisting of the contiguous Eugenio-Magano Farm 01 to Farm 03 (see Fig. 05)
The main water sequestration pond proposed will be located in Zone c (Figs. 01 and 02), at about the middle of Farm 03 (Fig. 04a and Fig. 4b). [Visit separate article for more detailed proposal and multiple use of the main water sequestration pond.]
Two other smaller water sequestration ponds will be located in Zone d (see Figs. 01 and 02, and the inclined area shown in Fig. 4a). These two smaller ponds will be located in the inclined portion of Zone d (Figs. 01 and 02), just North of the proposed main rainwater sequestration pond in Zone c (Figs. 01 and 2) visible as inclined portion of the image in Fig. 04a.
Fig. 01. Cadu Farm 03 Projects : Water Sequestration Ponds. The upper schematic map shown above is a top schematic view of Farm 03 with the proposed immediate and long terms projects to convert the Cadu farm 01 into a sustainable and biodiverse EcoCulture food production ecosystem. Just below the Top view map is a schematic representation of the lateral view of Farm 03 in Cadu, Ilagan. Fig. 02. presents a Schematic Map of Cadu Farm 03 without the proposed EcoCulture projects superimposed.
Terracing, and rainwater sequestration. Zone d is inclined (see Figs. 01 and 02, and the inclined area shown in Fig. 4a). Thus, it may be more prudent to create two water sequestration ponds instead of another single but larger pond, and terrace Zone d (see Figs. 01 and Fig. 02) with a combination of wide and tall soil embankments stabilized with biodiverse plants, and, organic dams created from compact rows of Vetiver grass. The terracing from the embankments and organic Vetiver grass dams will serve during the rainy season to slow down the flow rainwater coming from Zones e and f, and the adjacent lands North and East of Cadu Farm 03, as rainwater flows naturally towards the inclined Zone d down to Zone c (see Figs. 01 and 02).
Rainwater treatment. The rainwater collected during the monsoon season may be contaminated during the course of water runoff from one area to another -- especially rainwater collected from the road and from outside the Eugenio-Magano Cadu Farms. Further, massive infusion of rainwater, that may lack sufficient dissolved oxygen may destabilize the stabilized ecosystem developed in the multi-purpose main water sequestration pond (see Fig. 01 and separate article).
The smaller rainwater sequestration ponds or some of the canals may be used to treat and stabilize the raw rainwater runoff prior to addition of the treated water into the multi-purpose rainwater sequestration ponds.
Fig. 02. Schematic Map of Cadu Farm 03 without the proposed EcoCulture projects superimposed. The schematic map includes a Top view (Upper map) and a Lateral View (Lower map) representations, respectively, of Cadu Farm 03. The Lateral View (Lower map) reveals that Zones a, b and c are lower than Zones d, e and f. Zone d inclines down to meet with Zone c. Zone g is the lowest portion of Farm 03. At present, only Zones b and f have significant commercial crops, i.e., Mandarin Orange Trees (see separate articles on Mandarin Orange Groves and potential roles as windbreaks, and their potential use in intercropping and multiple cropping Various color schemes represent distinct regions of Farm 03, based on their unique vegetation or lack thereof, terrain, and other geophysical or manmade creations introduced in the evolution of Cadu Farm 03. Zone g, the lowest portion of Farm 03, includes the rice field plots (see separate article); however, it has not been cultivated for several years because the designated caretaker now takes care of his own lands in Ballacong that is equivalent to the combined area of Farm 01 and Farm 03.
Fig. 03. Schematic Map of Cadu Farm 03 with a number of the proposed EcoCulture projects superimposed.
Fig. 04a. Panoramic 180-degree view of Cadu Farm 03, taken from Zone c (see Figs. 01 and 02), showing a portion of the Mandarin Orange Groves in Zone b (see Figs. 01 and 02), the flat portion of Zone c revealing a tilled area (see Figs. 01 and 02), the inclined terrain of Zone d (see Figs. 01 and 02), and the boundary farm Northeast of Farm 03. From where the image was taken, Zone e (see Figs. 01 and 02) is barely visible while Zone f (see Figs. 01 and 02) is not visible at all. This observation reflects that the tilled field (Zone c, see Figs. 01 and 02) is much lower than Zones d, e and f (see Figs. 01 and 02).
Fig. 04b. Cropped image of the 180-degree view of Cadu Farm 03, enlarging the tilled field in Zone c (see Figs. 01 and 02). The background reveals the barely visible barangay road of Cadu going to Ballacong, as well as the much higher rolling hills across the barangay road. The concrete water drainage shown in the image was designed to empty during the rainy season the collected rainwater -- coming from the road and the adjacent higher rolling hills West of Cadu Farm 03 -- into the Zones c, b and a; perhaps even overflow into Zone g (see Figs. 01 and 02) area of Cadu Farm 03.
Flash Flood Mitigation and Flood Area Restriction
During the rainy season, based on the terrain and existing infrastructure, Zones c, b and a; and, perhaps even into Zone g (Figs. 01 and 02; and Figs. 4a and 4b), may be flooded frequently, especially during the high intensity torrential rains of a typhoon or storm that frequent Cagayan Valley during the monsoon season (July-November). The existing Maindarin Orange Trees (in Zone b) and other commercial crops planted in the aforementioned regions may not tolerate prolonged water logging.
One long term solution to the problem would be to create a deep main rainwater sequestration pond in Zone b, as proposed in Fig. 01. From our calculations, about 0.5-1.0 hectares of a 3-meter deep pond for every five (5} hectares of land area would suffice to sequester most of the rainwater during the height of the rainy season . The larger area would allow margin for even larger volume rainwater sequestration encountered during high intensity rain during the height of monsoon rains, as well as during the height of typhoon, and during La Nina.
While a deeper pond would provide more volume for rainwater sequestration, there may be issues encountered (e.g., dissolved oxygen content, light visibility, etc.) with a very deep water sequestration pond, if it is used also for other purposes, e.g., as an Aquaponics pond. However, natural lakes and even manmade dams may have depths greater than three (3) meters. One of the goals of our EcoCulture studies would be to investigate the impact and find solutions associated with the aforementioned issues.
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