1) Determination of feasibility of artificial recharge to upper Holocene aquifer for provision of fresh water for desalination of salinized abstracted groundwater by a rural domestic water supply facility in Thai Binh province;

2) Building of designs of two pilot of upper Holocene groundwater recharge and abstraction facilities in Thuy Truong and Thuy An communes, Thai Thuy district, Thai Binh province.

+ Salinity intrusion in the Hoa river: 1) In the present sea level, the maximal length of sea water intrusion is 16.671km in the dry season; 2) At sea level rise of 50cm, 75cm and 100cm the maximal lengths of sea water intrusion are 18.059km, 18.510km và 18.959km, respectively (which are greater than the present sea level 1.388km; 1.839km and 2.288m, corresponding to 8.33%, 11.03% and 13.72%); 3) Between the three levels of sea level rise of 50cm, 75cm and 100cm the increase of the length of the salinity intrusion is about 450m.
+ Desalination of groundwater aquifer along the Hoa river: 1) The groundwater abstraction wells along 1km along the river can provide from 60m3/day (in scenario with zero recharge from rainfall) to about 130m3/day (in scenario with groundwater recharge equal 10% for rainfall); 2) The Hoa river provides 64% (in scenario with zero recharge from rainfall) to 40% (in scenario with groundwater recharge equal 10% of rainfall) of the total abstraction rate; 3) The salt concentration of abstracted groundwater may decrease 35% since the 2.5th year of abstraction (The initial concentration of 2g/l decreases to 1.3g/l since the 2.5th year of abstraction); 4) The desalination area of upper Holocene aquifer in narrow: after 10 years of abstraction the desalination length (the border of salt concentration of 1g/l) is only 140m.
+ Groundwater recharge for development of additional fresh groundwater to desalination of brackish abstracted groundwater: 1) Facility in Thuy Truong commune: four recharging lakes (with an area of 20m2 and 3-m depth) and four well (with diameter of 2m and 8.5-m depth and drawdown 3.0m) can provide total abstraction rate 72m3/day (17.75m3/day for each well). For abstraction rate of 90m3 from Pleistocene aquifer with salt concentration of 1.84g/l the additional 72m3 of water with salt concentration of 0.2g/l would result in water with salt concentration of 1.12g/l; 2) Facility in Thuy An commune: eight recharging lakes (with an area of 25m2 and 3-m depth) and eight well (with diameter of 2m and 8.5-m depth and drawdown 3.0m) can provide total abstraction rate 131.2m3/day (16.4m3/day for each well). For abstraction rate of 400m3 from Pleistocene aquifer with salt concentration of 1.96g/l the additional 131.2m3 of water with salt concentration of 0.2g/l would result in water with salt concentration of 1.525g/l.
Based on the study results, designs of groundwater recharge and groundwater abstraction facilities have been carried out for development of additional fresh groundwater to bring down the salt concentration of abstracted groundwater at the rural water supply plants in Thuy Truong and Thuy An communes, Thai Thuy district, Thai Binh province.

- With the fluctuation of the coastal sea water level in the Thai Binh and Hoa rivers' mouth, there are certain time intervals of the days and months when the river water has salt concentration less than 1g/l which can be utilized for socio-economic needs of the area, and the differences of the salt intrusion lengths for the sea level rise of 50cm, 75cm and 100cm area about 450m.
- Quantitative results of the possible desalination of groundwater aquifer in time and space along the Hoa river with the help of the salt intrusion prevention gate to supply domestic water for commune and ward scale for the entire future;
- Dependently upon the scale of the artificial recharge and abstraction facilities, upon the rate of rainfall infiltration, an abstraction rate of 60m³/day to 170m³/day or more can be abstracted from an area of 1.5km² in Thai Thuy district.

- General report on the results of the research;
- Technical report: Provision of additional fresh water to rural domestic water supply in Thuy Truong and Thuy An communes, Thai Thuy district, Thai Binh province;
- Technical designs: Groundwater recharge and abstraction facilities for development of additional fresh water to rural domestic water supply in Thuy Truong and Thuy An communes, Thai Thuy district, Thai Binh province;
- Data sets: a) The Hoa river water's salt concentration in space and time; b) The groundwater recharge rates from the lakes and abstraction rates from the wells; c) The temporal abstraction rates of the groundwater abstraction wells along the Hoa river under different rainfall infiltration rates; d) Salt concentration of the groundwater abstracted water from wells along the Hoa river; e) Salt concentration of groundwater in the area between the Hoa river and abstraction wells in time

The project would like to recommend Department of Science and Technology of Thai Binh province transfer the results to Thai Binh province's DoNRE and DARD to implement the investment of the facilities in Thuy Truong and Thuy An communes.

The following future science and technology studies:
- Feasibility study of artificial recharge to Pleistocene aquifer in Hung Ha, Dong Hung and Quynh Phu districts to prevent the salinity intrusion into the fresh Pleistocene aquifer under present abstraction;
- Feasibility study of potential reservoirs to store and temporally store water from the Red, the Tra Ly and the Hoa rivers to develop additional fresh surface water resources and groundwater artificial recharge.
The project’s leader confirms hereby the veracity of all the details and information given above.