The hiti system is the cornerstone of the ancient water management system in the Kathmandu Valley, Nepal. The hiti system was introduced in the Valley even before the Lichhavi period (400-750 A.D.), and its network was expanded during the Malla period (Shrestha and Maharjan, 2016). A hiti (stone spout in English) is a traditional water resource usually present at a man-made depression in which water is channeled from a source to function as a tap. The traditional hiti system is an integrated water supply system that incorporates major sources of water i.e., rainwater, groundwater, and surface water resources. The hiti system consists of five major components:
Figure 1: Flowchart showing the working of the traditional water supply system.
- The conveyance canals and the rajkulos
- The stone spouts or the hiti
- The pukhus and wells
- The drainage system /
This traditional water system has served as one of the vital water sources required to meet water demands during dry days since ancient times. It is still actively used for drinking purposes by the locals residing in some core areas of the Valley. Recent studies have shown that the existing stone spouts of the Valley have been contributing to fulfill the water demands of about 10% of its population (Tripathi et al., 2019). Besides its significance in terms of water supply, the hiti system possesses considerable historical and cultural importance. However, the system has not been valued and often neglected by both the community and the state after the introduction of the modern piped supply system in 1950 A.D. (UN-HABITAT, 2008). At present, the traditional water supply systems (stone spouts, ponds, and wells) are in defunct conditions owing to the weak management capabilities of the government, the absence of proper policies, and lack of ownership. According to the Kathmandu Valley Water Supply Management Board (KVWSMB) report, there are 573 stone spouts and 233 ponds in the Valley, out of which 94 stone spouts and 40 ponds are completely lost (KVWSMB, 2019). Therefore, the existing traditional hiti system and its components should be monitored, conserved, and actions should be taken for the revival of the system.
Figure 2: Study area showing the location of monitoring wells and stone spouts.
Smartphones For Water Nepal (S4W-Nepal) has been monitoring the traditional hiti system of the Bhaktapur Municipality (BM) through a feasible citizen science approach. In order to monitor the hiti system of the BM, S4W-Nepal has recruited and trained 13 Citizen Scientists (CS) who are currently pursuing their bachelors. The CS have been recording monthly data of the discharge/quality of 16 stone spouts and the groundwater level/quality of 49 wells since 2019. Based on the collected data, S4W-Nepal aims to study the water distribution mechanism, the interactions of the stone spout with the neighboring wells and ponds, and also initiate the study on the possibilities of the revival of the system. Figure 2 shows the locations of the monitoring wells and stone spouts of S4W-Nepal. In the mid of every month, our CS measure the groundwater level using a measuring tape, and stone spout discharge by the help of a measuring cylinder. The stone spout discharge is calculated by determining the volume of water filled in the measuring cylinder within a certain period of time. Certain water quality parameters including temperature and Electrical Conductivity (EC) are also monitored using the HoneForest EC meter. An android application called Open Data Kit (ODK) Collect was used as a data collection platform.
Seasonal variation of groundwater levels and stone spouts discharge
A preliminary analysis has been carried out considering the monthly groundwater level and stone spouts discharge data collected by our CS from March 2019 to February 2021. The monthly data was transformed into seasonal data to understand the seasonal variation.
Figure 4: Boxplot showing the seasonal variation of stone spouts discharge from March 2019 to February 2021.
The boxplots (Figure 3 and 4) show the seasonal fluctuation of the groundwater level and stone spouts discharge in the period of two years (March 2019 to February 2021). The groundwater level was maximum during the pre-monsoon in both 2019 and 2020 and lowest during the post-monsoon in 2019 and monsoon in 2020. Similarly, the discharge was observed to be highest during the monsoon season in 2019 and post-monsoon in 2020. Over the study period, the discharge was lowest during the pre-monsoon season, followed by winter. However, it was found that the overall discharge of the stone spout in all four seasons was higher in 2020/2021 compared to 2019/2020. The higher precipitation in 2020 compared to 2019 is the possible cause for such variation in the groundwater level and stone spout discharge in the two years. The overall seasonal trend in the fluctuation of the groundwater level and stone spouts in both years was almost similar, indicating high dependence of the groundwater level and water discharge on rainfall. As the trend is similar in both boxplots, it can be assumed that there exists a certain degree of interactions between stone spouts and wells of the BM.
Interactions between stone spouts and wells in terms of EC
The parametric values of EC recorded by our CS in the two years were analyzed to understand the interactions of the wells and stone spouts. The above map (Figure 5) shows the spatial variations of EC in the stone spouts and wells of the BM. It can be observed that the well AW1 and stone spout BS3 lie nearer to each other and their EC values were also similar. Similarly, the stone spout CS3 and the wells CW1 and BW4 had close EC values. Furthermore, the stone spout CS5 and the well BW8 showed almost the same EC values. So, the aforementioned stone spouts and wells were found to interact in terms of EC and may have the same source. However, any strong conclusion can’t be drawn on the basis of this finding, since only one parameter was taken into account.
Furthermore, similar studies including multiple water quality parameters along with proper site selections should be carried out to fully comprehend the interactions between stone spouts and wells. The traditional hiti system is a very unique water heritage with great architectural and cultural significance and can serve as an excellent source of drinking water, particularly in the water-scarce region like the Valley. The degradation of traditional water resources not only causes a water supply deficit but also poses a significant influence on the historical and traditional aspects of the Valley. Therefore, the conservation and preservation of the existing traditional hiti system should be promoted and studies related to the feasibility for the revival of their components should also be initiated by the concerned authorities and organizations.
Shrestha, R.P. and Maharjan, K.L. (2016) Traditional water resource use and adaptation efforts in Nepal. Journal of International Development and Cooperation, 22(1&2), pp.47-58. Available from URL: https://core.ac.uk/download/pdf/222955771.pdf [Accessed 12th May 2021]
Tripathi, M., Hughey, K. F. D. and Rennie, H. G. (2019) The State of Traditional Stone Spouts in Relation to Their Use and Management in Kathmandu Valley, Nepal. Conservation and Management of Archaeological Sites. 20 (5-6), pp 319-339. Available from URL: https://www.tandfonline.com/doi/abs/10.1080/13505033.2018.1559421 [Accessed 12th May 2021]
UN-Habitat (2008) Water Movement in Patan: With Reference to Traditional Stone Spouts in Nepal. United Nations Information Centre, Kathmandu Nepal: United Nations Human Settlements Programme.Kathmandu Valley Water Supply Management Board, Government of Nepal (2019). Stone spouts and ponds of Kathmandu Valley. Kathmandu, Nepal: Government of Nepal, Ministry of Water Supply and Kathmandu Valley Water Supply Management Board.