The Ministry of Environment & Forests while clearing the project, had laid down certain conditions in their letter dated July 19, 1990. These conditions had enumerated certain studies which were to be carried out and, based on their findings, action plans had to be drawn up for execution pari-passu with construction of the project.
 All the required studies have been completed and their reports submitted to the Ministry of Environment & Forests (MOEF). These studies indicated that no environmental damage would be caused by the construction of the project, which cannot be remedied by adoption of appropriate measures. For this purpose, Action Plans, wherever called for, have been/are being implemented for environmental upgradation.
 Catchment Area Treatment: The status on the compliance of environmental conditions is briefly indicated below :
The CAT works had been under implementation right since 1983-84 as per guidelines applicable from time to time.  Subsequently, it was decided to treat only the  direct draining catchment area, of ‘high’ & ‘very high’ erodibility classification, based on satellite imageries.  Accordingly, a CAT Plan, 1994 was formulated for treatment of additional catchment area of 13,500 ha. In addition to the 22,746 ha. Area treated earlier.
Subsequently, based on the Govt. decision on Hanumantha Rao Committee recommendations, MOEF, in 1998, finalized CAT Plan for 52,204 ha. of high & very high Erodibility Areas in the Catchment.
The CAT works have been completed in 52,204 ha.  Area.
Command Area Development: The Command Area Development Plan(CADP) was submitted by the State GOUP and was forwarded by Ministry of Power to MOEF in July 1998. CAD Plan also included areas, which now form part of Uttaranchal. The existing canal networks will be utilized to irrigate extended cultivable  command area of 2.7 lac ha. as well as stabilize existing irrigation area in 6.04 lac. ha.  This system have to cater for drinking water supply also. Govt. of UP has submitted revised Command Area Development Plan to Ministry of Power and MOEF in January 2005.
Flora & Fauna: As per MOEF stipulation, the studies were conducted through Botanical Survey of India(BSI) for flora and Zoological Survey of India(ZSI) for fauna affected due to reservoir. The reports were submitted to MOEF in 1993. The BSI has revealed that no rare species come under submergence of reservoir and, hence, the construction of the proposed dam will no way lead to extermination of any species. The BSI study recommended plantation of certain species. The plantation work has been completed  accordingly by Forest Deptt., Government of Uttaranchal (GOUA).
 The setting up  of a Botanical Garden at Koti which is located adjacent to the Reservoir has been completed through the State Forest Deptt.   The Botanical Garden has been planned to preserve important flora of the region. A high-tech nursery is having the endemic species  coming under submergence
 As suggested by ZSI, action plan for possible mitigation of Mahseer fish had been framed through M/s Tropical Fisheries Consultants Ltd., and submitted to MOEF in 1994. The Implementation of Action Plan for Mahseer fish was taken up in consultation with the Director, National Research Centre on Cold Water Fisheries Station, ICAR, Bhimtal. The Mahseer Fish hatchery & fish farm site has been developed near Koteshwar Dam (20 Km D/S of Tehri Dam). The works of the establishment of hatchery work has been completed Breeding work and further operations are in progress.
 In addition to Mahseer fish, other fish species brooder viz. common crap,  and snow trout has also been taken up with National Research center on cold  water fisheries (ICAR),  Bhimtal.
 Water Quality: The water quality modeling study had been carried out by the University of Roorkee, now IIT, Roorkee (report furnished to MOEF in 1992). The study had concluded that no specific measures are required and there would be no adverse effect on the water quality due to impoundment.
THDC in consultation with CWC has identified five water quality monitoring station. THDC through Pollution Control Research Institute, BHEL, Haridwar, (approved by Central Pollution Control Board) is carrying out the work on water quality monitoring both upstream and downstream of Tehri Dam  is being carried out 
Central Water & Power Research Station (CWPRS) also carried out mathematical model study on water circulation and concluded that water in reservoir remains under dynamic circulation throughout the year and does not remain stagnant. Dissolved Oxygen (DO) and Bio-Chemical Oxygen Demand (BOD) in whole of reservoir are expected to remain within permissible limits desired for drinking water source.
Disaster Management Plan :The Disaster Management Plan (DMP) was prepared by THDC, and was submitted to the  Ministry of Agriculture (MOA), who are the Nodal Ministry for this purpose, in April 1992. After deliberations, the Ministry of Agriculture had, on 24.02.99, conveyed approval to the DMP. In the review meeting of DMP held in August,2000. It was also decided that GOUP may be associated with this exercise so that in the line up of actions required at various stages, and the State Governments DMPs at district levels be dovetailed with the DMP of THDC, so that authorities / persons concerned in the warning systems, discharge operation system, communication, command and control of emergencies are defined at different levels and responsibilities defined by name / designation.
 GOUP have vide office order dated;19.4.2002 constituted a Steering Group under the Chairmanship of Principal Secretary, Irrigation Deptt. to deal with emergency situations and to dovetail the State Govts. DMP at District levels with the DMP of THDC.
 GOUA have vide office order dated;28.1.2003 also constituted a Steering Group under the Chairmanship of Principal Secretary( Irrigation & Energy)  to deal with emergency situations and to dovetail the State Govts. DMP at District levels with the DMP of THDC.
Bhagirathi River Management Authority: GOUP had issued an Administrative Order for setting up of the Authority in March’90. GOUP  constituted Bhagirathi River Valley Authority on a statutory basis vide notification dated; 14.07.99. After the formation of GOUA, the State Govt. of Uttaranchal has also constituted the said Authority in the year 2003 adopting UP enactment.
 Again vide notification of January 27, 2005, River Valley Authority have been established under Uttranchal River Valley Development & Management Act 2005.
 Impact on Human Health: For studying the potential health aspects of Tehri Dam Reservoir, the matter was taken up with Director General of Health Services (DGHS) requesting them to arrange study on the subject. As per directions of DGHS, National Malaria Eradication Programme (NMEP) & Malaria Research Centre(MRC) carried out detailed field investigation of the project area in March’99 and Sept.,99 and recommended in July,2000 mitigation measures. Accordingly, recommendations of DGHS, CMO, Tehri has prepared an Action Plan which will be implemented after impoundment. Necessary preparatory actions have also been taken.