River Infrastructure Is More Than Water Management
Indonesia faces a high risk of hydrometeorological disasters, including floods. Heavy rainfall, monsoon cycles, and the country's extensive river network make water-resource management a critical issue for public safety, agriculture, transportation, and regional development.
When river infrastructure deteriorates, the consequences can extend far beyond the damaged structure. Failed embankments, damaged groundsills, and weakened revetments can increase flood risks, threaten agricultural areas, disrupt transportation routes, and affect local economies.
The researchers therefore examined river infrastructure from a broader perspective. In addition to its engineering and flood-control functions, river infrastructure can contribute to national resilience by protecting communities and maintaining essential transportation and logistics routes.
Indonesia's total defense doctrine also recognizes that national security involves more than military capabilities. Under Law No. 3 of 2002 on State Defense, national resources—including civilian infrastructure—can contribute to protecting the country's sovereignty, territorial integrity, and public safety. Natural disasters such as floods are also recognized as non-military threats that require preparedness.
The Progo River Basin as a Strategic Case
The Progo River Basin covers approximately 243,833 hectares across Central Java and the Special Region of Yogyakarta. The river supports technical irrigation and helps control flooding in communities along its course toward the Indian Ocean.
The strategic importance of the river became particularly visible during an incident in Srandakan, Bantul Regency, in January 2025. Extreme rainfall upstream sharply increased the Progo River's discharge, damaging a 160-meter retaining structure and threatening the stability of Srandakan Bridge.
The incident demonstrated how river infrastructure can affect transportation connectivity between regions. Structures such as groundsills also help control local erosion around bridge foundations, reducing the risk of scour that can threaten bridge stability.
For emergency response and national resilience, maintaining these connections is critical because roads and bridges allow people, goods, emergency assistance, and resources to move during disasters.
Researchers Analyzed 88 River Structures
The study used a quantitative approach based on secondary data from the Serayu Opak River Basin Agency (BBWS Serayu Opak). Rather than selecting only part of the population, the researchers analyzed all 88 river structures recorded in the Progo River Basin asset inventory.
The data covered the AKNOP value, operation and maintenance budget realization, structural condition, structure age, structure type, and river-segment location. Structural condition was measured on a scale from 0 to 100 based on field assessments.
Among the 88 structures, 72 units, or 81.8 percent, were groundsill or crib structures. Another 10 structures, or 11.4 percent, were embankments, while six structures, or 6.8 percent, were revetments.
Most of the structures—84 units or 95.5 percent—were located in the downstream segment of the basin.
Because the data did not meet the normality assumption required for conventional regression analysis, the researchers applied rank regression, a statistical approach that can be used when data distributions depart from normality.
Average Structural Condition Reached 70.34
The study found that the average condition score of the 88 structures was 70.34 on a scale of 0 to 100. The scores ranged from 50 to 90, indicating that the typical structure was in relatively good condition but still required systematic maintenance.
The AKNOP values varied considerably, ranging from approximately IDR 3.57 million to IDR 664.02 million. Meanwhile, budget realization averaged 51.76 percent, with individual structures ranging from 3.25 percent to 96.40 percent.
AKNOP should not be interpreted simply as a measure of how damaged a structure is. The index is calculated using work volume and unit costs. Consequently, a large structure can have a high AKNOP value even when its physical condition remains relatively good.
Conversely, a smaller structure with deteriorating conditions may have a lower AKNOP value because its required work volume is limited. The researchers emphasized that AKNOP primarily reflects the scale of maintenance needs rather than structural damage alone.
AKNOP and Budget Realization Explained 87.1 Percent of Variation
The statistical analysis showed a significant relationship between AKNOP and structural condition. The t-value for AKNOP was -16.737, with a significance level of 0.000.
Budget realization also showed a statistically significant relationship with structural condition, producing a t-value of -2.361 and a significance level of 0.021.
When AKNOP and budget realization were analyzed together, the model produced an F-value of 118.237 with a significance level of 0.000. Most notably, the adjusted R-square reached 0.871, meaning that the two variables jointly explained 87.1 percent of the variation in the ranked structural-condition scores.
The negative coefficients require careful interpretation. The researchers do not conclude that higher maintenance spending makes river infrastructure worse.
Instead, the negative relationship reflects the way AKNOP and maintenance priorities are structured. Structures with greater maintenance needs may receive larger budget allocations because their condition requires more urgent intervention.
This interpretation was supported by validation involving seven water-resource experts and practitioners. The priority-based budget realization dimension received the strongest support, with a mean score of 4.64 out of 5, equivalent to approximately 89 percent agreement. Overall expert validation reached a mean score of 4.34 out of 5, with 80.6 percent agreement.
Condition-Based Maintenance Can Strengthen Resilience
The findings point to the importance of using actual field conditions to determine maintenance priorities. Rather than distributing limited funds equally among all structures, agencies can direct resources toward infrastructure requiring the most urgent intervention.
For flood mitigation, this approach can help preserve the function of embankments, groundsills, revetments, and other river structures. It can also reduce risks to bridges and transportation routes affected by erosion and flooding.
The study also connects river maintenance with non-military defense. Well-maintained civilian infrastructure can protect communities, preserve regional connectivity, and support the movement of people, goods, and emergency resources during disasters.
The researchers recommend that BBWS Serayu Opak formally document its maintenance-priority mechanism so that the process remains transparent, auditable, and consistent. They also recommend conducting another structural-condition assessment in 2028.
The 2028 assessment would allow researchers and infrastructure managers to compare conditions with the 2023 baseline and determine how structures changed after a full maintenance cycle.
Authors' Profiles
Research Source
Article Title: AKNOP, Budget Realization, and River Structure Performance in Flood Mitigation: A Quantitative Study of the Progo River Basin as Non-Military Defense Infrastructure
Authors: David Carlos Methlis Mone, Jupriyanto, and Gregorius Henu Basworo
Affiliation: Defense Industry Study Program, Faculty of Defense Science and Technology, Republic of Indonesia Defense University
Journal: Indonesian Journal of Advanced Research (IJAR)
Volume: 5, No. 8
Year: 2026
Pages: 1335–1348
DOI: https://doi.org/10.55927/ijar.v5i8.16917
https://journal.formosapublisher.org/index.php/ijar
The article was published in the Indonesian Journal of Advanced Research (IJAR) as an open-access research article.
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