When the Casili Underwater Cave System (CUCS) was first explored on Aug. 23, 2011 by the late Dr. Alfonso Amores and Bernil Gastardo, they saw a lush, tranquil environment adjacent to a flowing river.

Along the banks of the spring and the river, thick foliage and expansive acacia trees gave the visitors a visually appealing ambiance and fine shades to rest under.

The image of Casili has drastically changed since Dec. 2014 after a deluge brought by a storm drastically removed significant portions of the land on each side of the meandering Arpili river bank. Additionally observed is the reduction of the river’s water flow.

The area’s potential as a source of business has also been realized by the local community which resulted in small sari-sari stores set-up by enterprising individuals selling food and drinks to a growing stream of visitors drawn to the cool waters of the spring. All of these actions are creating an impact to the spring’s already fragile ecosystem. Cave diving trips organized by foreign divers and dive shop owners are also noted.

But there are more dire issues at hand. Clear observations from the 2015 preliminary assessment of the spring by the team that was working under the support of GIZ & BMB – Protected Area Management Project (PAME) illustrates the importance of the area to the community and of its long term survival which rests on the decisions makers of the municipality that it belongs to.

This assessment which still highlights and reflects the current situation of the Casili spring environment was presented to the Balamban LGU. It preceded by around 6 months the comprehensive official report for the project titled “Rapid Resources Assessment of 4 Underwater Caves in the Philippines” of which CUCS was included.

At present, the FCD is not aware of any implemented actions from the recommendations listed in the said assessment.


Casili Spring & Cave Preliminary Assessment
Sitio Casili, Barangay Arpili,
Balamban- Cebu

Jan. 2015


The Casili Spring is an important aspect of life for the residents of Sitio Casili. Most households acquire their drinking water in the spring and most bathe and do their laundry in the mid and downstream portions. Recently, it has also become a local tourist destination that residents from nearby barangays and municipalities. Furthermore, the spring and the adjacent river is an important source of food for most households.

The type of fish that locals prize is the “casili/ba-is” an eel that was reported to be formerly abundant and is where the sitio and spring got its name. It is a native delicacy, which is cooked with coconut milk and local spices. It has been reported that some eels reach sizes of 12 to 20 inches in length and 3 to 4 inches diameter. People usually hunt the eel at night, during the onset of a full moon, using hook-and-line method and use small fish as bait. The most recent report of an eel being caught was last December 2014.

Immediate threats to Casili Spring

In comparing the topography of the banks of the Casili Spring during a DENR-FCD site inspection last October 10, 2014 with the present survey, a substantial chunk of the river bank, approximately 843.75 m2, separating Casili Spring from the main river system has been lost to erosion from strong flood waters during the onslaught of Typhoon Senyang last December 2014.

The loss of the narrow piece of land separating the Casili Spring from the main river system would not only integrate the Casili Spring with the Arpili River but also destroy the habitats of possibly new and endangered flora and fauna, as well as the loss of the iconic symbol of Barangay Arpili.

Interviewed local residents reported that some non-locals catch freshwater fish and shrimp using poisonous substances.

Another is the presence of trash along the mouth of the spring and trash inside the cave (as reported by the FCD during their cave mapping survey). Other observed threats include the use of soap for bathing and laundry which may increase phosphates/ sulfates and exacerbate eutrophication downstream.

Recommendations for mitigation measures

Flooding and erosion are caused by many factors but probably one of the most significant causes of erosion in the riverbank separating the Casili Spring and the main river system is the lack of large indigenous trees lining the riverbanks.

Because of this problem, it is highly recommended that a combination of short and long-term solutions be implemented in this particular area as soon as possible, such as the reinforcement of the weakened river bank using rip-raps and the planting of large indigenous trees with extensive root systems that have the potential to hold and retain soil (i.e. bamboo, Balete, etc.).


• The spring is an important freshwater resource for the local residents and LGU
• Around 71 households rely on the water of the spring for domestic uses.
• Ecotourism has a strong potential in the area. Tourism for local and foreign nationalities with activities such as bathing, swimming, guided tours.
• Biodiversity is relatively high despite the lack of protection and given the small size of the area. The site is a possible refuge for new and endemic species.
• It is an indicator of water quality around adjoining area and above the underwater spring.
• It is a possible indicator of disturbance of the aquifer from activities around the vicinity (e.g. deforestation, farming and quarrying)
• Potential for high value ecotourism such as Cave diving (awaiting classification and approval of Government Agencies).

CUCS 2018-Oct.jpg
Recommendations in order of Urgency:

I. Immediate action on riverbank reinforcement and protection

o Construction of rip-rap is urgent
o Planting of indigenous trees along the river banks (i.e. bamboo, Balete, etc.)
o Other reforestation activities along the vicinity using endemic tree species.

II. Passage of Barangay and Municipal Ordinance for Protection and Ecotourism

III. MOA among stakeholders (land owner, LGU, other agencies)

IV. Registration and monitoring of visitors

V. Regular detail of Barangay Tanods on the site

VI. Community Environmental Education

Assessment Team:

• Bernil H. Gastardo
• Jaime Lapac
• Juan Naval
• Alex Santos

USC-Biology Department:
• Dominic Franco Belleza
• Dave Valles
• Fidel Bendanillo
• Richard Parilla

• Joel B.Carino
• Alberto Villacruel
• Richard Diaz

Much appreciation goes to the support given by:

GIZ- Deutsche Gesellschaft für Internationale Zusammenarbeit GmbH

BMB- Biodiversity Management Bureau

DENR- Department of Environment and Natural Resources


October 2018

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January 2015

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August 2011

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